Abu Musab al-Zarqawi, al Qaeda's chief ally in Iraq, may be planning attacks on "soft targets" in the United States including movie theatres, restaurants and schools, Time magazine has reported.White House national security adviser Stephen Hadley would not discuss the specific warning, which Time said was circulated among U.S. security agencies last week in a restricted bulletin.
But he said the administration was concerned about reports -- "which we think are very credible" -- that Zarqawi is working more closely with Osama bin Laden's al Qaeda organisation.
Hadley said movie theatres, restaurants and schools "are the kinds of targets we know that al Qaeda has traditionally been concerned about."
"But we, at this point sitting here, do not have evidence of a specific operation by Zarqawi's organisation targeting those kinds of targets. We just don't have that kind of information at this point," Hadley told CNN's "Late Edition."
The warning comes two weeks after President George W. Bush, in a rare public mention of the mastermind of the September 11, 2001, attacks, said stopping bin Laden from a new attack on U.S. soil was "the greatest challenge of our day."
Time said the bulletin was based on the interrogation of a member of Zarqawi's organisation.
It cited Zarqawi's belief that "if an individual has enough money, he can bribe his way into the U.S.," by obtaining a visa to Honduras and then travelling across Mexico and the southern U.S. border.
But the magazine quoted intelligence agencies as saying there is no evidence that Zarqawi's agents have infiltrated the United States.