Washington ? Searching for ways to expand international forces in Iraq, the Bush administration for the first time is exploring the creation of a multinational military force under United Nations leadership, but still subordinate to U.S. commanders, Deputy Secretary of State Richard Armitage said.

The solution would be designed to give the United Nations a greater role in the Iraqi occupation in return for increased support of the U.S.-dominated peacekeeping mission, administration officials said. Without a strong U.N. mandate, a number of countries have been reluctant to send troops.

U.S. officials emphasized Wednesday that the concept was one of several under discussion as the administration seeks stronger military and financial backing for Iraqi reconstruction without surrendering American control. There is no agreement yet within the administration, and neither the Pentagon nor the White House has signed off.

The Bush administration is facing growing pressure to resolve Iraq’s continuing instability at a time when thinly-stretched U.S. forces are struggling to halt guerrilla assaults, violent crime and a recent spurt of deadly terrorist attacks. Armitage’s remarks to regional reporters, released Wednesday, reflect a difficult effort to share the burden more widely.

While some U.S. politicians, including Sen. John McCain, R-Ariz., and Sen. Joe Biden, D-Del., have urged the deployment of thousands more U.S. soldiers, others have sought ways to limit the exposure of American troops, who have been killed at the rate of one every two days since May 1.

The administration’s willingness to consider creation of multinational peacekeeping force under a U.N. mandate could signal an important shift, since Defense Secretary Donald Rumsfeld and other senior officials have thus far been reluctant to cede any U.S. authority regarding reconstruction and stability operations.

Informal discussions on a possible U.N. resolution are under way in at the United Nations in New York and key foreign capitals. Secretary of State Colin Powell is leading this effort as he did last spring’s unsuccessful bid for U.N. Security Council approval of the Iraq invasion, officials said Wednesday. Draft language designed to attract more troops and money could be circulated next week, said diplomats who cautioned that a solution seems distant.

At the Security Council, key officials from France, Germany and Russia who opposed the war in Iraq remain deeply skeptical about authorizing a new multinational force that would operate under U.S. command. They believe the United States should yield greater political and economic control to the United Nations and other governments that contribute troops.

Some council diplomats also want the United States to cede a measure of political authority inside Iraq. They have called on the administration to set a firm timetable for the establishment of a representative government and a schedule for the withdrawal of U.S. and British forces from Iraq.

Rumsfeld favors an increase in foreign troops, but has long been opposed to a formal U.N. command. He declared as recently as Monday, “I think that’s not going to happen.” He offered no indication of how he might react to a hybrid arrangement in which the Pentagon’s overall control of military operations would be preserved.

Armitage became the first administration official to suggest publicly that U.S. and U.N. officials are exploring the possibility of an adjustment to the force structure. He described the concept as “a multinational force under U.N. leadership, but the American would be the U.N. commander.”