Libya Attacks Came in Two Waves, Official Says BENGHAZI, Libya - The mayhem here that killed four United States diplomatic personnel, including the ambassador, was actually two attacks - the first one spontaneous and the second highly organized and possibly aided by anti-American infiltrators of Libya's young government, a top Libyan security official said Thursday. The account by the official, Wanis el-Sharif, given to a few reporters here, was the most detailed yet of the chaotic events on Tuesday in this eastern Libyan city that killed J. Christopher Stevens, the first United States ambassador to be killed on duty in more than 30 years. The deaths occurred amid a wave of anti-American protests convulsing the Middle East, inspired by an inflammatory anti-Islamic video, "The Innocence of Muslims," that has spread on the Internet in recent days since it was publicized in Egypt. Protests expanded on Thursday to at least a half-dozen other countries, including Iran. Mr. Sharif, a deputy interior minister, said Mr. Stevens and a second American diplomat, Sean Smith, were killed in the initial attack, which began as a disorganized but angry demonstration by civilians and militants outside the American Consulate on Tuesday, the anniversary of the Sept. 11, 2001, attacks. The protest escalated into an assault by as many as 200 people, some armed with grenades, who set the building on fire. The second wave, Mr. Sharif said, was hours later, when the consulate staff was being spirited to a safe house a mile away. At that point, a team of Libyan security officials was evacuating them in a convoy guarded by Marines and Libyan security officials who had been flown from Tripoli to retrieve them. Mr. Sharif said the second attack was a premeditated ambush on the convoy by assailants who were armed with rocket-propelled grenades and apparently knew the route the vehicles were taking. The other two Americans - identified on Thursday as Tyrone S. Woods and Glen A. Doherty, both former members of the Navy SEALs - were killed in that assault. At least 12 Americans and 18 Libyan security officials were wounded, Mr. Sharif said. The first part was chaotic and disorganized. The second part was organized and planned," he said. The ambushers in the second assault, he said, apparently "had infiltrators who were feeding them the information." Parts of Mr. Sharif's account were not consistent with what other Libyan witnesses have said, and his version has not been corroborated by American officials, who have said it remains unclear how and where Mr. Stevens was killed. Many Libyans considered Mr. Stevens a hero for his support of their uprising against Col. Muammar el-Qaddafi. Two Libyans who were wounded while guarding the consulate said that, contrary to Mr. Sharif's account, there was no indication within the consulate grounds that a mass protest, including members of armed groups, had been brewing outside. The guards spoke on condition of anonymity for their personal safety, and one of them said he realized the dangers only about 9:30 p.m., when protesters crashed through the gate and "started shooting and throwing grenades." The other guard said that he had been drinking coffee inside the compound just before the attack, and that it was so quiet "there was not even a single ant." Mr. Sharif spoke as Libyan officials said at least four people were in custody. The Obama administration, which has vowed to bring the killers to justice, has sent 50 Marines and two warships to Libya, and the F.B.I. has joined the investigation. But it remains unclear precisely what American military firepower can do. If the attackers were not part of a larger international plot, there are no obvious targets for American retaliation. "These are not the kind of guys with training camps and caravans to hit," said Michael W. S. Ryan, an expert on Islamic militants at the Jamestown Foundation, a research group in Washington. The worst of the video-inspired violence on Thursday was in Yemen, where at least five Yemenis were killed as hundreds of protesters stormed the American Embassy in Sana and were repulsed by Yemeni security forces. The embassy's staff, sensitive to the danger, had been safely evacuated hours before, and Yemeni leaders apologized to President Obama for the mayhem. The attackers set cars on fire and plundered offices of their equipment, including computers. They also burned an American flag and hoisted their own standard proclaiming fealty to Islam. By nightfall, witnesses said, smoke was still rising from the embassy compound in the eastern part of the capital as a protest raged 400 yards away. In Egypt, where the anti-American anger began on Tuesday, protesters scuffled with police officers who were firing tear gas, and news agencies reported that as many as 200 people might have been hurt. Demonstrations were also reported outside United States diplomatic missions in Morocco, Sudan and Tunisia - where the police fired tear gas to disperse the crowds - and an anti-American protest was held in Gaza. In Iran, where nearly all large protests must get government approval, witnesses and news reports said 500 people screaming "Death to America!" converged at the Swiss Embassy, which handles American diplomatic interests, and were restrained by hundreds of police officers. The authorities in Afghanistan, where deadly violence has repeatedly flared over perceived insults to Islam, scrambled to keep the video, which portrays the Prophet Muhammad as a perverted buffoon, from being seen. Afghanistan officials said they pressed to indefinitely suspend access to YouTube, where the video, promoted by a shadowy assortment of right-wing Christians in the United States, had been viewed more than 1.6 million times by Thursday. In Washington, Secretary of State Hillary Rodham Clinton said Mr. Woods and Mr. Doherty - the two victims identified on Thursday - had served multiple tours in Iraq and Afghanistan before going to work as contract security officers for the American diplomatic mission in Libya. Mr. Woods, she said in a statement on Thursday night, was married and had three sons and was a registered nurse and a certified paramedic. He and Mr. Doherty died "helping protect their colleagues," she said. Mrs. Clinton also delivered a strongly worded denunciation of the video in what her spokeswoman later said was an effort to quash the belief in some parts of the Arab world that the United States government had somehow sponsored or condoned it. "To us, to me personally, this video is disgusting and reprehensible," Mrs. Clinton said at a briefing with Morocco's foreign minister. It appears to have a deeply cynical purpose: to denigrate a great religion and to provoke rage. The killings in Libya led to a major political flare-up in the United States on Wednesday, when Mr. Obama's Republican challenger, Mitt Romney, issued a harsh critique of the president's handling of the protests and accused him of apologizing for the United States. The administration rejected the accusation, and even some Republicans distanced themselves from Mr. Romney's criticism as inappropriate under the circumstances. The Yemen protests came hours after a Muslim cleric, Abdul Majid al-Zindani, urged followers to emulate the protests in Libya and Egypt, residents in Sana said. Mr. Zindani, a onetime mentor to Osama bin Laden, was named a "specially designated global terrorist" by the Treasury Department in 2004. The crowd in Sana gathered a day after the embassy warned Americans in a posting on its Web site that "in the wake of recent events in Libya and Egypt, there is the possibility of protests in Yemen, and specifically in the vicinity of the U.S. Embassy, in the coming days." Suliman Ali Zway reported from Benghazi, Libya, and Rick Gladstone from New York. Reporting was contributed by Nasser Arrabyee from Sana, Yemen; Alan Cowell from London; Ramtin Rastin from Tehran; David D. Kirkpatrick from Cairo; Kareem Fahim from Beirut, Lebanon; and Steven Lee Myers, Scott Shane and Michael S. Schmidt from Washington.