A roadside bomb struck an Iraqi army patrol on Sunday in the western flashpoint city of Fallujah, killing four soldiers, witnesses and medical sources said.

"A roadside bomb went off early in the morning on the main street in central Fallujah as an Iraqi army passed by, killing four soldiers aboard and wounding others," a local resident told Xinhua on condition of anonymity.

"We have received four bodies and five wounded Iraqi soldiers, one of them was seriously wounded," said a medical source, who refuse to disclose his name.

Local residents said that masked armed men attacked a U.S. military base last night in central Fallujah with gunfire and rocket propelled grenades.

"Many attackers opened fire at the U.S. base, as gunfire and explosions could be heard across the city," the witnesses said.

Another U.S. military base, located two km east of Fallujah, was also attacked by rockets at about 10:30 p.m. (1930 GMT) on Saturday, the witnesses said.

"I saw two rockets heading to the U.S. base followed by loud explosions and sirens wailed in the base," a witness said.

He added that "five minutes later, the U.S. artillery fired back at the source of the rockets, but it was not clear whether there were casualties among the both sides."

The U.S. military did not confirm the information from Fallujah.

The Sunni-dominated Fallujah, some 50 km west of Baghdad, has witnessed sporadic insurgent attacks against the U.S. and Iraqi government forces despite U.S.-Iraqi military operations in the city to stamp out insurgency.

Source: Xinhua