As the Bush administration rejects an overture by Afghanistan's Taliban government, Attorney General John Ashcroft is warning of a "very serious threat" of additional terrorist attacks. 

A Taliban envoy said discussions might be possible to ease the impasse over Usama bin Laden if the United States offers evidence linking him to the Sept. 11 attacks in New York and at the Pentagon. White House chief of staff Andrew Card replied that "the president has said we're not negotiating."

"They've got to turn not only Usama bin Laden over but all the operatives of the Al Qaeda organization" that bin Laden runs, Card said on Fox News Sunday.

With little sign of anything besides a military solution in sight, Ashcroft said that "we believe there are others who may be in the country who would have plans" for more attacks.

"Frankly, as the United States responds, that threat may escalate," Ashcroft said on CBS' Face the Nation.

"We're very confident that Usama bin Laden, Al Qaeda, terrorist organizations are operating in dozens and dozens and dozens of countries around the world," Ashcroft added on CNN's Late Edition.

Taliban leader Mullah Mohammed Omar told his people in a radio address not to worry about a U.S. attack because "Americans don't have the courage to come here."

As for bin Laden, "He's in a place which cannot be located by anyone," Taliban ambassador to Pakistan Abdul Salam Zaeef told journalists in Islamabad.

In Afghanistan, opposition forces maintain that they've gained territory and that hundreds of Taliban soldiers defected during three days of fighting in northern mountains.

The U.S. government turned to defense at home, designating retired Army Gen. Wayne Downing to coordinate intelligence and military resources in the anti-terror campaign. Richard Clarke, who currently heads the government's counterterrorism team, will direct efforts to protect the nation's information infrastructure from attack.

Clarke and Downing will serve President Bush at the National Security Council, working alongside Tom Ridge, who was tapped by Bush to head a newly created Cabinet-level Office of Homeland Security.

Citing the continuing threat, Ashcroft urged Congress to provide "the tools to prevent terrorism" by dramatically increasing federal officials' ability to perform electronic surveillance, punish terrorists and detain non-citizens.

Bush wants to see the legislative package passed by Friday, but House and Senate Judiciary committee schedules indicate that it will be at least mid-October before the two chambers even have a starting point to begin negotiating.

Some lawmakers have questioned whether some of the provisions infringe on civil liberties. "I think everybody knows that we're going to have to make sure that we have some kind of a check-and-balance in there," Senate Judiciary chairman Patrick Leahy, D-Vt., said on Face the Nation.

In other developments:

— The Saudi ambassador said two dozen members of bin Laden's family were flown out of the United States following the attacks, most of them students evacuated under FBI supervision.

— Several thousand anti-war demonstrators marched Sunday in the capital to call for peace following the terrorist attacks. "We're here to honor and mourn the victims of the violent attacks," said Maria Ramos, coordinator of the Washington Peace Center, which helped organize the march. "Calling a criminal act an act of war gives it too much dignity."

— As Americans slowly return to the skies and while security remains tight and time-consuming, the federal government is allowing some airports to resume the timesaving measure of curbside baggage check-in.

— In an interview with the BBC on Sunday, British Prime Minister Tony Blair said he has seen "absolutely powerful and incontrovertible evidence" linking bin Laden to the Sept. 11 attacks.

— Trial resumed in Afghanistan for eight foreign aid workers accused by the Taliban of spreading Christianity. The top judge told the workers, who include two Americans, that the threat of U.S. military action would not affect their case.