The machinery of war and diplomacy rolled forward side-by-side at the White House on Saturday as the Bush administration prepared for imminent decisions about military action in Iraq by both international allies and the president.

President Bush, who usually spends weekends at Camp David, stayed at the White House where a few thousand anti-war protesters gathered off the back lawn.

Bush remained in town to attend Saturday evening's annual Gridiron dinner. In a nod to the "seriousness of the times," spokesman Taylor Gross said Bush would trade the traditional presidential comedy routine for serious, though brief, remarks to the gathered media elite.

In his weekly radio address, Bush reiterated his case for quick action against Iraq's Saddam Hussein, suspected of possessing banned weapons of mass destruction.

"As a last resort, we must be willing to use military force," the president said. "We are doing everything we can to avoid war in Iraq. But if Saddam Hussein does not disarm peacefully, he will be disarmed by force."

The president spoke by phone with President Hamid Karzai of Afghanistan about his embattled country's reconstruction. Bush was planning to put off until Monday more calls to foreign leaders to try to win support in the U.N. Security Council for a U.S.-British-Spanish proposal that paves the way for war, a White House official said.

The new resolution, due for a vote next week in New York, faces strong opposition from veto-wielding council members and not yet enough backing yet from others to pass, even without a veto. Newly amended, the proposal would give Saddam until March 17 to totally disarm.

If the resolution fails, as seemed likely, military action could come within days, officials have said. The timetable is less certain if it passes.

Secretary of State Colin Powell planned appearances on three separate Sunday news shows to continue the diplomatic and public relations effort.

On Saturday, Deputy Defense Secretary Paul Wolfowitz and Deputy Secretary of State Richard Armitage met in the West Wing's situation room with national security adviser Condoleezza Rice and White House chief of staff Andrew Card.

In Iraq, where U.S. and British aircraft are enforcing northern and southern flight-interdiction zones established after the 1991 Persian Gulf War, fighters over the southern zone struck for a second consecutive day Saturday against mobile surface-to-air missile guidance radar systems.

The U.S. Central Command said both strikes used precision-guided weapons after "in response to Iraqi threats to coalition aircraft."

Meanwhile, in the streets of Washington, women united against war pledged to rally a nation of daughters, mothers and grandmothers in a push for peace.

The surprisingly balmy weather had several thousand people chanting and cheering at a rally before their planned march to the Ellipse just south of the White House. The event was organized by the group calling itself CodePink, the name a protest against the government's color-coded terror alert system.

Activists wore their color of peace in many forms, from scarves to sweaters and even pink bathrobes for some men.

"A lot of us are mothers and grandmothers and we identify with the women of Iraq who will suffer the most," said Sara Hinkley, 31, of Oakland, Calif.