Eyewitnesses say three explosions were heard in the direction of  the west bank of the river Tigres, an area is close to the US-led coalition headquarters in the city.

A US military spokesperson has confirmed that there were two quick successive blasts in the capital, which may have been caused by rockets or mortars.

If confirmed this would be the third attack on the Iraqi capital by insurgents this week.

Insurgents fired at least three mortars or rockets at the US-led headquarters on Tuesday evening, wounding four people. Mortars were also fired at the compound on Monday night.

Those blasts occurred inside the US-controlled "green zone", a sprawling area formerly home to one of Saddam Hussein's palaces and which includes US military bases and the headquarters of the occupation forces which ousted Saddam Hussain in April.