BAGHDAD (Reuters):

Five United States soldiers were killed in Iraq on the weekend, raising the number of American troops killed this month to over 100, and making April one of the deadliest of the war for U.S. forces.

The toll could increase the pressure on U.S. President George W. Bush, who is fighting a plan by Democrats to set a timetable for withdrawing U.S. forces from Iraq.

Bush has vowed to veto a war spending bill from Democrats that requires combat troops to begin withdrawing by October 1. The Democrat-controlled Congress plans to send the bill to Bush today. The U.S. military said yesterday three soldiers and an Iraqi interpreter were killed by a roadside bomb in eastern Baghdad on Sunday. A Marine was killed in western Anbar province on Sunday.

Another soldier was killed by small arms fire in eastern Baghdad on Saturday, the military said.

U.S. and Iraqi forces launched a major security crackdown in Baghdad in mid-February that is seen as a final attempt to halt Iraq's plunge into all-out civil war between majority Shi'ites and once-dominant minority Sunni Arabs.

United States commanders acknowledge that the offensive, which has led to the deployment of thousands of extra troops on the streets, has increased the risk of military casualties.

Before the announcement of the latest deaths, the independent casualties.org website had put the number of U.S. troops killed in Iraq in April at 99. Around half have been killed in and around Baghdad.

Some 3,350 U.S. troops and many tens of thousands of Iraqis have been killed since the U.S.-led invasion in 2003.