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. 
 
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 This story was originally published on ||||| A policeman standing guard Wednesday at the Rosa Khutor Park in the Krasnaya Polyana complex, which will be used for skiing at the upcoming games. | Reuters 
 
 Amid heightened concerns about security at the upcoming Sochi Winter Games, Russia has introduced extensive safeguards that observers say are close to those imposed in a state of emergency. But some countries' teams will be providing their athletes with even more security, worrying that the level of danger in Sochi is higher than at any previous Olympics. 
 
 Some 2,000 athletes will participate in the Games, and about 213,000 visitors are expected to come to Sochi, which borders Russia's turbulent North Caucasus republics. The Games will be held in the wake of two recent suicide bombings that killed 34 people in Volgograd, 700 kilometers north of Sochi. 
 
 Many nations said that while they were concerned about the Volgograd attacks, they would primarily count on the Russian authorities to provide security during the Games. Part of the U.S. team, however, has hired a private security firm for its athletes, while the U.S. government has sent FBI agents to Sochi and Moscow for the duration of Games and made air and naval assets available to help Russia prevent possible terror attacks. 
 
 Several groups have threatened to attack the Sochi Olympics, the latest being a group that calls itself Vilayat Dagestan, which also claimed responsibility for the Volgograd bombings. They said the attacks were ordered by rebel leader Doku Umarov, who has also threatened to strike Sochi during the Olympics. 
 
 In response to the possible threats, the U.S. ski and snowboard team has hired private security firm Global Rescue to protect its athletes in case of emergency. Global Rescue head Daniel Richards said Sochi was a unique environment with challenges that his firm had not experienced at the Winter Olympics in Turin, Italy, in 2006 or Vancouver, Canada, in 2010, when its security agents also worked for the U.S. team. 
 
 For the Sochi Games, the firm will have five aircraft on standby to assist the team in case an emergency requires an evacuation. Richards said it would be one of the firm's larger deployments for the U.S. Ski and Snowboard Association given the scale and the location. "Our planning with them began months ago," he said by e-mail. 
 
 Global Rescue is also providing athletes with guidelines to minimize the possibility that they would become targets and develop protocols and strategies they can use to deal with events that might occur while they are in Sochi. He said his firm's team would work with Russian state agencies as necessary. 
 
 Britain has also said it will provide additional security to its Olympic team by sending security staff to Sochi as part of its delegation, but said the move is not related to last month's attacks in Volgograd. 
 
 Alexander Demianchuk / Reuters A ski lift operating at a Sochi venue. 
 
 "We will rely primarily on the security provided by the Games Organizing Committee and the host country," the British Olympic Association said in a statement following the Volgograd bombings. "As with previous Olympic Games, we will have security personnel as part of our delegation. That has been in our planning all along." 
 
 The statement said that in the interests of secrecy, neither the exact number of security personnel nor where those individuals will be based would be disclosed. 
 
 Russia's security services are taking what some observers say are unprecedented measures to provide sufficient protection from would-be attackers. 
 
 Some 40,000 police officers will be used to provide security during the Olympics, and Russia's 58th Army unit, which is composed of about 70,000 soldiers, will patrol Russia's nearby southern border with Georgia. 
 
 By comparison, at the 2012 Summer Olympics in London, some 13,000 police officers and 17,000 soldiers were used for security. 
 
 "Security is to be ensured by some 40,000 law enforcement and special services officers," President Vladimir Putin said in an interview with foreign media on Sunday. "We will protect our air and sea space, as well as the mountain cluster. I hope things will be organized in such a way that they do not catch the eye and will not, so to say, depress the participants in the Olympic Games." 
 
 Some nations, even those that have experienced tragedy at past Olympics, say that they consider these measures sufficient and that they will not be sending additional security for their teams. 
 
 Israel, which saw 11 of its Olympic team members taken hostage and later killed by Palestinian terrorists at the 1972 Summer Games in Munich, is among them. Vladimir Shklyar, head of the Israeli delegation to the Sochi Olympics, said by phone that Israel was confident that Russian security agencies would do their job properly and that the Games would be safe. 
 
 A spokesman for the German Olympic Sports Federation said Germany also trusted Russian authorities to provide excellent security in Sochi. "But we will look closely with our German national security authorities on the situation in Sochi, because in the modern world you can never be 100 percent confident that there will be no emergency situations," he said. 
 
 The spokesman said he could not reveal whether German security officials would be a part of the German delegation or would observe the situation from Germany. When asked whether the team would use the services of a private security firm like Global Rescue, he said: "We will have no aircraft, that is all that I can say." 
 
 A representative for the Dutch Olympic Committee said he could not comment on whether the Netherlands would take any additional security measures but said: "We take security seriously, just like the authorities in Sochi." 
 
 From Sweden, only one special pair could demand a security detail — and it is not the star athletes from their cross-country skiing squad. 
 
 "We rely on the host country's authorities — only the king and queen can get additional security personnel," said a spokesman for the Swedish Olympic Committee.
– The US has sent two warships to the Black Sea and put planes on standby in Europe as it prepares to evacuate its Olympians from Sochi in the event of an attack. But officials fear their preparations might not be enough, reports NBC News, which describes the effort as "logistically mind-boggling and diplomatically delicate." The big issue: The US can't do much without Russian permission, and it doesn't expect to get that. "Something that looks like the US cavalry riding to rescue Russia … well, it's just hard to imagine that happening," one Russian expert said. The US skiing and snowboarding teams have signed up their own private security company, Global Rescue, which claims it has six aircraft ready for an evacuation if necessary. But having planes isn't the only issue; it's having runways. Sochi's airport is fairly small, so deciding which of the 85 countries competing to use it would be a nightmare. Other teams are also taking special security precautions, the Moscow Times reports. Britain, for example, is sending extra security personnel with its delegation. A German spokesman, meanwhile, said the country trusted Russia, but would "look closely" at the situation. "We will have no aircraft, that is all that I can say."