Seventeen suspected terrorists, identified as possible conspirators in a planned attack on the United States, could have ties to the al-Qaida network.
U.S. Attorney General John Ashcroft told an assembly of police chiefs in San Antonia, Texas Tuesday they need to be on the highest alert for a terrorist attack that could take place at any time.
Mr. Ashcroft said many of the 17 men could be associated with fugitive terrorist mastermind Osama bin Laden.
Mr. Ashcroft's reinforce the earlier alert issued Monday by the U.S. Federal Bureau of Investigation, which calls on Americans to remain on the lookout for a Yemeni man named Fawaz Yahya al-Rabeei.
The FBI website pictures him along with 12 other suspects. Four additional suspects are on the watchlist but no photographs are posted.
Federal authorities say they learned about the plot from detainees held at the U.S. naval base at Guantanamo Bay, Cuba and in Afghanistan.
The latest warning is the most specific since the September 11 attacks on the United States. An alert issued on December 3 has been extended through the Winter Olympics now under way in the U.S. state of Utah.