One US soldier was killed and three others were wounded when their vehicle was hit by a roadside bomb in an eastern Baghdad neighborhood on Saturday, a US military spokesman said.

"According to initial reports, we believe one soldier was killed in an IED (improvised explosive device) attack. The bomb hit some sort of armored support vehicle, larger than a Humvee," the spokesman said.

US soldiers have sealed off the site of the explosion and a CNN reporter who tried to approach the scene was detained for more than half an hour.

Military helicopters could be seen evacuating the casualties, and witnesses said no Iraqis were killed or injured in the incident.

Ali Saleh, 23, told Xinhua he was having dinner indoor when he heard the thunderous explosion, which smashed his windows.

He went out and saw an armored vehicle destroyed some ten meters away and at least ten casualties were evacuated by a helicopter.

"The vehicle might have run over the bomb, but it was really more powerful than any roadside bomb I have ever seen on TV," he said.

Ali said he did not notice any persons who had planted the bomb outside his garden, and insisted that he would never allow any attackers to do so near his house.

The attack took place in the morning close to the place of an ambush on Friday near the Shiite populated neighborhood of Sadr City in eastern Baghdad. Five soldiers were killed and four others wounded in the ambush.

According to the US military, 602 of its soldiers have been killed in combat actions and more than 210 others died in non-combat incidents since the launch of the US-led invasion of Iraq inMarch 2003.