Baghdad, Jan 5 : Iraqi Prime Minister Nuri al-Maliki has said his country would file a lawsuit against US private security firm Blackwater over the killing of Iraqi civilians here two years ago.

Maliki has rejected a US judge's decision to drop charges against five Blackwater security guards who were involved in killing unarmed civilians at a crowded intersection in western Baghdad in 2007, Xinhua reported Tuesday.

The Iraqi government will initiate legal proceedings against the company in the US and Iraqi courts and "we reject the ruling issued by the American court acquitting the company of the crime of killing a number of citizens", Maliki said in a statement Monday.

In September 2007, security guards of Blackwater opened fire on dozens of civilian cars at the busy Nissor Square, killing 17 people and wounding several others.

Guards protecting US embassy personnel were given immunity from prosecution in Iraqi courts after the invasion in 2003.

Earlier, the Iraqi parliament and some top officials also rejected the US judge's decision to throw out charges against the US guards and demanded an appeal to prosecute the defendants.(IANS)