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BAGHDAD, May 4 (Reuters) - Four U.S. soldiers were killed and nine others wounded in three separate incidents in Iraq on Thursday, the U.S. military said on Friday.

In the deadliest attack, one soldier was killed and six others were wounded when their vehicle was struck by a roadside bomb in eastern Baghdad, the military said in a statement.

Another soldier was killed and three others wounded when a roadside bomb hit their vehicle in western Baghdad in an attack in which an Iraqi translator also died.

In western Iraq, two soldiers were killed in combat in the province of Anbar.

U.S. and Iraqi troops launched a security crackdown in Baghdad in February to crack down on sectarian death squads and militants.

U.S. commanders say the operation, seen as the last-ditch hope to avert Iraq from sliding into sectarian civil war, has put U.S. soldiers at a greater risk.

Roadside bombs are the deadliest weapon against U.S. forces in Iraq. U.S. commanders are particularly concerned about the increased use of a more lethal and sophisticated type of roadside bombs known as explosively formed penetrators, or EFPs, which are capable of penetrating armour.

The U.S. military says EFPs components are fabricated in neighbouring Iran.

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