Unknown gunmen opened fire at the convoy of the Iraqi President Adel Abdul Mehdi in western Baghdad on Thursday, an Interior Ministry source told Xinhua.

"Mehdi was with the convoy when the gunmen attacked his convoy, but it was not known whether there was any casualty," the source said on condition of anonymity.

He said that "we have just called in a U.S. military support according to an urgent demand from Mehdi's lieutenant who said they were surrounded by the attackers."

It was not clear whether Mehdi was hurt by the attack, the source added.

In separate incident, a car bomb went off near an Iraqi army patrol almost at the same area, causing undetermined casualties, a well-informed police source said.

"A car bomb parking near the Nafaq al-Shurta (Police Tunnel) area detonated at about 11:20 a.m. (0820 GMT) near a passing Iraqi army patrol," the source told Xinhua on condition of anonymity.

It was not clear whether there was any casualty as the area is guarded by the Iraqi army who cordoned off the scene, he said.

However, witnesses at the scene told Xinhua that an Iraqi army Humvee was ablaze.

Source: Xinhua