Maxim Shemetov / Reuters file Sochi's Olympic Park is seen in December. 
 
 A catastrophic terrorist strike at the Sochi Winter Olympics would present the United States with a logistically mind-boggling and diplomatically delicate challenge: How to get more than 200 American athletes safely out of Russia. 
 
 U.S. military officials have described plans to use two warships in the Black Sea and planes already on standby in Europe to evacuate Americans if the worst fears of security experts come true. 
 
 But these are the Olympics of President Vladimir Putin, who is spending a reported $50 billion on the games, including a purportedly impenetrable “ring of steel” around the Olympic city, and who sees the games through a prism of national pride. 
 
 Any American rescue operation would depend heavily on his approval, security experts say. And that’s unlikely if not impossible. 
 
 NBC News' Richard Engel reports from inside the difficult-to-reach Coastal Cluster in Sochi. 
 
 “As far as being able to do things without Russian cooperation, it’s basically a nonstarter,” said Andrew Weiss of the Carnegie Endowment for International Peace, a former Russia expert in the Clinton White House and an NBC News analyst. 
 
 “This is their territory, their country,” he said. “They get to decide what kind of outside help they need.” 
 
 Fears of Olympic terror have grown in the countdown to the games, which formally open Feb. 7. In the past week, a militant video has promised a “surprise” in Sochi, and Russia has hunted for at least five suspected terrorists who may have designs on an attack. 
 
 On Tuesday, police said they had killed a senior Islamist militant in Russia's North Caucasus as they hunted three Muslim women dubbed “black widows” and other terror suspects ahead of the Winter Olympics. 
 
 So while Putin’s ring of steel may help thwart larger coordinated attacks, experts are warning that lone attackers also pose a significant threat to the Games. 
 
 According to Gordon Woo, terrorism expert at risk management modeling firm RMS, analysis shows that terror plots involving up to 10 operatives have a 5 percent chance of succeeding. 
 
 Ezra Shaw / Getty Images Snowboarder Kelly Clark at a competition earlier this month. 
 
 "Smart terrorists" rein in their ambition and aim for simpler plots with fewer operatives, he said. 
 
 The U.S. Olympic Committee declined to discuss the details of security for the American athletes or what would happen in the event of an evacuation. 
 
 “The safety and security of Team USA is our top priority,” Patrick Sandusky, a USOC spokesman, said in a statement. 
 
 “As is always the case, we are working with the U.S. Department of State, the local organizers and the relevant law enforcement agencies in an effort to ensure that our delegation and other Americans traveling to Sochi are safe,” he said. 
 
 But at least part of the American contingent for Sochi, the skiing and snowboard teams, is paying a private company, Global Rescue, for additional security. 
 
 The company promises communications help, “rally points” for athletes to shelter in place and ways to get them around, or out of, Sochi. Dan Richards, the CEO, said in an interview that Global Rescue has six aircraft that it could “utilize for rapid response.” 
 
 Exactly how that would work — a private security company landing its planes in or around Sochi in the immediate aftermath of an attack — is not clear, and Richards declined to provide details of the company’s plans. 
 
 Global Rescue also offers its services to individuals and companies, and in recent years has helped customers during the Arab Spring, the earthquake in Haiti and the tsunami and nuclear crisis in Japan. 
 
 Counterterrorism analyst Michael Leiter says transportation in Russia is vulnerable in the high-threat areas surrounding Sochi. The terrorists who previously launched an attack, he said, have every incentive to do so again. 
 
 “In every major crisis we’ve been involved with, we’ve never had host governments deny us overflight or landing permission,” he said. “The likelihood is that we’ll all work together, the Russians, our government, other friendly government and other private companies.” 
 
 Richards would not say what the U.S. Ski and Snowboard Association is paying for the additional protection. The skiers and snowboarders are among the richer American teams. 
 
 The American luge team — 10 athletes and four coaches, plus medical and support staff — will rely on the U.S. Olympic Committee, said Gordy Sheer, the team’s director of marketing and sponsorship. 
 
 “They’re working pretty hard, and we’ve been given a lot of assurances,” he said in a phone interview. “I feel that the USOC is really making it a priority, and obviously the Russians are as well.” 
 
 There are signs of concern among American athletes. Some, including at least two members of the high-profile hockey team, have told their families not to travel to Sochi to cheer them on. 
 
 “I’m actually really concerned about it,” Zach Parise, one of the hockey players, told the Star Tribune of Minneapolis-St. Paul. “I know they say they have evacuation stuff for us and all, but you just never know. I guess you have to wonder at what point does someone say it isn’t a good idea for us to go.” 
 
 The biathlon team has bought satellite phones for its coaches and is recommending that traveling families of its 10 athletes purchase medical and evacuation insurance — the same already provided to Olympic athletes by the USOC — should anything go wrong, said Max Cobb, president and CEO of U.S. Biathlon. 
 
 Other American athletes say their minds are on getting ready for competition. 
 
 “I’m not worried about any safety issues in Russia at this point,” said Kelly Clark, a snowboarder competing in her fourth Winter Games. “We’re so focused on our competition and on our sport.” 
 
 U.S. officials say the terror threat is higher than at any previous Olympics. The State Department will have diplomatic security officers in Sochi, though it has declined to say how many, and the FBI will have a presence as well. 
 
 Evan Vucci / AP file President Barack Obama and Russian President Vladimir Putin last June. 
 
 “The Russian government has the lead here for security,” Marie Harf, a State Department spokeswoman, told reporters. “Obviously we’ve said we’re happy to assist in any way we can, certainly for American citizens.” 
 
 President Barack Obama spoke with Putin this week about Olympic security, and Russia has raised the possibility of the Americans’ sharing bomb-detecting technology for the games. That would mean having American military personnel on the ground to help. 
 
 But senior defense officials told NBC News on Wednesday that there was little or no chance that the technology could be in place in time. It would take months to train the Russians, and there has been no discussion of using the system in Sochi under total American control, they said. 
 
 And the Olympics take place at a time of frayed U.S.-Russian relations — tested by the Edward Snowden affair and the Boston Marathon bombings — not to mention the long shadow of the Cold War. 
 
 A large-scale attack would trigger almost unimaginable complications, said Weiss, the Russia expert. 
 
 For example: At least 85 countries and 2,500 athletes are taking part in the games. Sochi has a fairly small airport, so who gets to fly out first? And why should the Americans be given priority? 
 
 “Something that looks like the U.S. cavalry riding to rescue Russia or Vladimir Putin from an attack seems — well, it’s just hard to imagine that happening,” he said. “Ultimately, it’s all on Russia.” 
 
 Catherine Chomiak, Courtney Kube, Jim Miklaszewski, Andrea Mitchell and Michele Neubert of NBC News contributed to this report. 
 
 Related: 
 
 This story was originally published on ||||| (CNN) -- A video surfaces threatening the Winter Olympics. Russia's President vows the Games will be safe. Some U.S. lawmakers warn that they won't be. 
 
 One thing was clear as debate over the situation surged on Sunday: security is a top concern, less than three weeks away from the competition. 
 
 "It's a very serious fear," Sen. Angus King, I-Maine, told CNN's State of the Union Sunday. 
 
 Russian President Vladimir Putin acknowledged that the Games, like any high-profile event, could be a target for terrorists. 
 
 But, he said, Russia has a "perfect understanding" of the threat and how to stop it. 
 
 As a transcript of his interview with half a dozen national and international broadcasters was posted on the Kremlin website Sunday, a video that surfaced online again highlighted the security situation. 
 
 In the video, posted on a well-known Jihadi forum website, two young men believed to have been suicide bombers in last month's back-to-back bombings in the Russian city of Volgograd speak of those attacks and make an ominous promise. 
 
 "We've prepared a present for you and all tourists who'll come over," the video says. "If you will hold the Olympics, you'll get a present from us for the Muslim blood that's been spilled." 
 
 Attack on transit hub fuels concerns 
 
 In the video, the men are dressed in black and standing in front of a black banner with religious verse that is typically associated with al Qaeda-linked extremists. 
 
 Last month's attacks in Volgograd, a major transit hub about 650 kilometers (400 miles) away from Sochi, sparked concerns over security as the Olympics approach. 
 
 The explosions targeted a train station and a trolley bus and claimed the lives of more than 30 people. 
 
 In addition to the Volgograd attacks, there has also been violence in recent days in the southern republic of Dagestan -- the latest unrest linked to a long-running Islamist insurgency in the North Caucasus region. 
 
 Putin pledges stepped up security 
 
 Putin has pledged that visitors to Sochi for the Winter Olympics will be kept safe. 
 
 "We will try to make certain that the security measures are not intrusive or too conspicuous, so they are not too noticeable for the athletes, the Olympics' guests or journalists," Putin said, according to the interview transcript. 
 
 "But at the same time, we will do our utmost to ensure that they are effective." 
 
 Russia has plenty of experience in keeping international events secure, Putin said, pointing to the G8 and G20 summits as examples. 
 
 "Security is to be ensured by some 40,000 law enforcement and special services officers," he said. "Of course, we will draw on the experience acquired during similar events held in other regions of the world and in other countries. It means that we will protect our air and sea space, as well as the mountain cluster." 
 
 U.S. lawmakers: Games aren't safe 
 
 But several U.S. lawmakers offered a different take Sunday on CNN's State of the Union. 
 
 King, a member of the Senate Intelligence Committee, said he wouldn't go to the games himself, "and I don't think I would send my family." 
 
 Rep. Mike Rogers, chairman of the House Intelligence Committee, also called on the Russian government to be more cooperative with the United States on intelligence sharing ahead of the games. 
 
 "Their level of concern is great, but we don't seem to be getting all of the information we need to protect our athletes in the Games. I think this needs to change, and it should change soon," Rogers said. 
 
 When asked whether he thought Americans would be safe at the Games, former CIA and NSA director Michael Hayden said he trusts Russia's ability to provide security. 
 
 "I think Americans will be quite safe," he said. 
 
 Putin: 'No danger' for gay visitors 
 
 Russia's stance on gay rights has been another area of concern for many visitors. 
 
 Russia has come under international pressure since its parliament passed a law last summer outlawing "gay propaganda." The legislation makes it illegal to tell children about gay equality and has been widely criticized by Western leaders, who have called it archaic and discriminatory. 
 
 But Putin defended it before journalists Friday, saying that the law was about protecting children. 
 
 "We have just recently passed a law prohibiting propaganda, and not of homosexuality, but of homosexuality and child abuse, child sexual abuse. But this has nothing to do with persecuting individuals for their sexual orientation," he said. 
 
 "So there is no danger for people of such nontraditional sexual orientation who are planning to come to the Games as guests or participants." 
 
 Russia has also been criticized over the limitations placed on freedom of speech at Sochi. The official protest site is about a 30-minute drive from the Olympic village and is difficult to find. 
 
 But Putin said no visitors should fear problems if they protest, for example, over gay rights. 
 
 Putin says gays 'can feel safe' at Sochi Winter Olympics 
 
 Putin: No corruption 
 
 The Russian leader also dismissed claims that corruption has pushed up the cost of the games, saying there was no proof that had occurred. 
 
 When it won the bid in 2007, Russia said the Winter Games would cost $12 billion, but the government's website now cites the total cost as 1.5 trillion rubles ($45 billion.) 
 
 "I do not see serious corruption instances for the moment, but there is a problem with overestimation of construction volumes," Putin said. 
 
 He suggested the problem was a universal one, where companies underestimate costs in the tendering process in order to win the project, and then push the price back up. 
 
 But, he said, there was no evidence of anything that could be considered corruption, or "theft of public funds with the help of state officials in whose hands these funds fall," in Sochi. 
 
 "If anyone has such information, give it to us, please. I repeat once again, we will be grateful. But so far there was nothing but talks," he said. 
 
 Putin put the cost of preparations for the Winter Olympics at only 214 billion rubles ($6.4 billion) but acknowledged that the total sum, including the cost of major infrastructure projects, was much higher. 
 
 The total price tag of $45 billion outstrips the $40 billion China is thought to have spent on the Beijing Summer Games and is more than three times the cost of the London Games in 2012. 
 
 Boris Nemtsov, former deputy prime minister of Russia and a vocal critic of Putin, published a report last year describing the Sochi games as one of the most "outrageous swindles" in recent Russian history. He claimed that up to 60% of the final cost -- or $30 billion -- has been embezzled. 
 
 CNN's Nic Robertson in Sochi, Virginia Harrison in London and Greg Clary in Washington contributed to this report.
– An ominous new report on Vocativ says the Sochi Olympics may be the most extreme, security-wise, in the history of the Games—the site describes "a gulag-style restricted area" instituted by Vladimir Putin. The Christian Science Monitor calls the restricted zone the "ring of steel," an area 60 miles wide and 25 miles deep that will be patrolled by tens of thousands of security troops and in which everyone "will be subjected to near total surveillance." Air Force fighters, drones, anti-aircraft missiles, and anti-saboteur patrol boats will be deployed. Travel in and out of the city will be restricted; public protests and marches will be banned. But the most ominous part: According to the Monitor, some worry that even these measures may not be enough. The biggest potential threat appears to be the North Caucasus Islamic insurgency and Chechen Islamist warlord Doku Umarov, leader of the Caucasus Emirate terrorist group, who has promised an attack at the Games. But there are others, experts warn, who are similarly interested in terrorizing Sochi. "When we examine these recent Volgograd attacks, it's hard not to notice how well planned and well organized they were. They seem to have enjoyed a lot of logistical help," says one expert. "Terrorism has become a big business, and there are people with a real, material interest in keeping it going." A rebel news outlet has been decrying Putin's security measures, Vocativ reports, noting that the lockdown starts today—a month before the Games start—and lasts until March 21, nearly a month after they end.