Government officials are warning of a possible second wave of terrorist strikes in the United States as the FBI tries to determine whether some of the hijackers involved in last week's attacks were traveling under stolen identities.
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• FBI Uncertain of Hijackers' Identities • Terrorist Manhunt Continues • New Arrest Made • Possible Terrorist Stock Trading Probed
"We do expect more attacks," a senior Bush administration official said today. "We're at the point where anything is possible, but nothing can be predicted."
Law enforcement and intelligence sources tell ABCNEWS the FBI believes there is a strong possibility a network of terrorists is still in place in the United States preparing to launch additional attacks.
"We … have continuing concerns about the people responsible for Tuesday's attacks and information that does suggest they might have planned further attacks," said one senior intelligence official, who asked not to be identified. "But we don't have any intelligence that gives us specific dates or methods for those attacks."
Capitol Hill sources who have been briefed by the CIA tell ABCNEWS that intelligence points to an "umbrella plan" to destabilize the country.
Check back for continuous updates on the hunt for terrorists from ABCNEWS' worldwide investigative team.
• Possible Identity Crisis
There is now confusion about the real identities of the 19 men pegged by investigators as the terrorists who hijacked four planes on Sept. 11, crashing two into the World Trade Center, and a third into the Pentagon. The FBI acknowledged today some of the terrorists may have been traveling under aliases and stolen names.
"We have several hijackers whose identities were those of the names on the manifest; we have several others who are still in question," FBI Director Robert Mueller said while touring the site where the fourth hijacked plane, United Airlines Flight 93, crashed in Shanksville, Pa.
A Saudi Arabian official told ABCNEWS two of the men named as hijackers of the four planes that crashed have been confirmed to be alive and well.
The FBI has named Abdulaziz Al-Omari as one of the hijackers believed to have piloted American Airlines Flight 11 into the North Tower of the World Trade Center. But a Saudi man has reported to authorities that he is the real Al-Omari, claiming his passport was stolen in 1995 while he studied electrical engineering at the University of Denver.
The Saudis say they have confirmed Al-Omari left the United States on Sept. 3 and has proved that he was working in Riyadh when the attacks happened.
Newspapers in the Middle East also reported three others named as hijackers by the FBI — Saeed Al-Ghamdi, Mohald Al-Shehhi and Waleed Al-Shehhi — are alive.
• FBI Manhunt Continues