Four people were killed and one injured in Iraq Thursday by unknown gunmen and a roadside bomb, while an army base came under rocket attack overnight.

A local official in Fallujah, some 60 km west of the capital Baghdad, survived an assassination attempt, but two people with him - including his brother - were killed, witnesses said.

They said the official, Farouk al-Kartan, was not injured. The unknown gunmen quickly fled the scene.

Earlier, a senior finance official at the Iraqi Ministry of Higher Education had been killed by unknown gunmen in Baghdad.

Jamal Shehab, head of financial affairs at the ministry, was shot and killed near his home in the neighbourhood of al-Amraniya, security sources said.

In the southern city of al-Hilla, meanwhile, one Iraqi soldier was killed and another injured while they tried to defuse a roadside bomb, which exploded during the operation.

The incident took place in the area of Jarf al-Saghr in al-Hilla, some 100 km south of Baghdad.

Five Katyusha-type rockets also hit the headquarters of the Iraqi army's 10th division outside the south-eastern city of Amara late Wednesday night, the Aswat al-Iraq news agency reported.

Security forces found and sealed off the area from which the rockets were launched, around 5 km south of Amara.

Police found 13 other rockets in the launching area.

The United States officially ended its combat mission in Iraq this week. Its remaining 49,700 troops will only have advisory, training and counterterrorism roles until they too leave in 2011.