The number of U.S. soldiers that died in Iraq reached 4,000, after a roadside bomb killed four U.S. soldiers and wounded another in Baghdad on Sunday, shortly after President Bush had declared in a speech that the United States is on the way to victory.

The bomb exploded near the soldiers’ vehicle, while they were patrolling in southern Baghdad around 10 p.m.

A few hours earlier, the same day, a mortar shell fell on a house in central Baghdad, killing a family with three children.

Many rockets and mortar shells also fell Sunday evening on the Green Zone, injuring at least five people. The zone hosts the embassies of U.S. and other countries, as well as Iraq’s parliament and cabinet.

Sunday’s violence did not stop here. Iraqi police also reported 10 civilian deaths due to mortar explosions in various areas of eastern Baghdad, during which 20 other civilians were also injured.

The number of 4,000 dead soldiers will probably cause controversy again among those who oppose the war and those who support it.

The death toll reached 1000 in September 2004, 18 months after the invasion started. Then it climbed to 2,000 in October 2005 and to 3,000 in December 2006.

"I doubt the 4,000 milestone will have the impact that the 3,000 did. The conventional wisdom then was that things were going badly," said Stephen Biddle, a senior fellow for defense policy at the Council on Foreign Relations in Washington, according to the Washington Post.

US soldiers said in an interview with the AFP news agency in Iraq, that even though the number of 4,000 deaths is tragic, the conflict is justified and the soldiers involved in the war were aware of the dangers when they voluntarily joined the army in Iraq.