The Bush administration pressed Congress to take the lead in authorizing force against Iraq Wednesday after the U.S. campaign for a tough new U.N. resolution was undercut by Saddam Hussein's offer on inspections. As the White House talked tough, United Nations weapons inspectors began planning their return to Baghdad.

"It serves no U.S. or U.N. purpose to give Saddam Hussein excuses for further delay,'' Defense Secretary Donald H. Rumsfeld asserted.

Iraq's announcement that it would accept the return of international weapons inspectors nearly four years after they left divided the Security Council. The United States and Britain pursued a resolution to force Iraq to disarm. But Russia and France were opposed, as were Arab nations.

Rumsfeld, in testimony to the House Armed Services Committee, and President Bush, in a White House meeting with top congressional leaders, dismissed the Iraqi leader's 11th-hour overture as a stalling tactic.

"He's not going to fool anybody,'' Bush said.

Rumsfeld suggested that Iraq had concealed evidence of its weapons programs in a labyrinth of tunnels and other elaborate hiding places, certain to complicate and prolong any new inspection effort.

While United Nations officials in New York prepared for the inspectors return, the United States and Britain began working on a new resolution aimed at authorizing use of force should Baghdad fail to comply with U.N. Security Council resolutions.

Western diplomats said the U.S.-British draft would likely include new instructions for weapons inspectors and a timetable for disarmament that would be tighter than one laid out in an existing resolution passed in December 1999.