BAGHDAD, Iraq -- The United States soon will trim its military force in Iraq to slightly below 138,000 troops, the level it has considered its core force this year, Defense Secretary Donald H. Rumsfeld and other U.S. officials hinted Thursday.

The cuts, probably in the 5,000 to 7,000 range, would be achieved by canceling the planned deployment to Iraq of two Army brigades and could be announced as early as Friday, officials said.

The reduction would bring the troop level in the insurgency-torn country to just above 130,000 sometime in the spring, said one U.S. Defense Department official who spoke on condition of anonymity because an announcement was not yet finalized.

The reductions discussed Thursday would come in addition to Rumsfeld's previous announcement that about 20,000 troops are to return home after bolstering security during Iraq's fall elections.

There were 159,000 U.S. troops in Iraq on Thursday. The American force peaked at 192,000 during the March 2003 invasion; the monthly low was 109,000 in January 2004.

Also in Baghdad, Sunni Arab and secular Shiite factions demanded Thursday that an international body review complaints about voting fraud in last week's elections and threatened to boycott the new legislature. But the United Nations rejected the idea.

The demand for a review came two days after preliminary returns indicated the current governing group, the Shiites' United Iraqi Alliance, was getting bigger than expected majorities in Baghdad, which has large numbers of Shiites and Sunnis.

Although final results are not expected until January, secular Shiites and Sunni Arabs were alarmed. The formerly dominant Sunni minority, in particular, fears being marginalized by the Shiite majority, which was oppressed during Saddam Hussein's reign.

But the criticisms of the election could also be part of jockeying for position by both Sunnis and former Prime Minister Ayad Allawi, a secular Shiite, before negotiations begin on forming a new coalition government. No group is expected to win a majority of the legislature's 275 seats.

The complaints came as foreign officials conducted high-profile surprise visits to Iraq to meet with their countries' soldiers before Christmas.

British Prime Minister Tony Blair visited troops in the southern city of Basra, U.S. Defense Secretary Donald H. Rumsfeld stopped in Baghdad and Polish Prime Minister Kazimierz Marcinkiewicz met with soldiers in central Iraq.

Saddam's trial adjourned until Jan. 24, after two days of testimony in a case tied to the deaths of more than 140 people in the town of Dujail after an assassination attempt against the Iraqi leader in 1982.

A suicide car bomb and several shootings killed more than a dozen people across Iraq, including six police officers, authorities said.