Washington, Jan 9 (DPA) The US government is reviewing options for proceeding with the prosecution of five Blackwater contractors accused of killing innocent Iraqi civilians in a September 2007 shooting.

US State Department spokesman P.J. Crowley said Friday that a Dec 31 decision by a federal judge to dismiss manslaughter charges against the five security guards does not 'exonerate the defendants or necessarily terminate the proceedings'.

'The Department of Justice, in consultation with the State Department, will carefully review the judge's decision and assess all available legal options,' Crowley said.

Blackwater Worldwide, a North Carolina-based firm that has since changed its name to Xe Services, is contracted by the State Department to provide private security to US personnel and diplomatic convoys in dangerous parts of the world.

The charges against the five guards arose from a shooting in Baghdad's Nisour Square that left 34 unarmed Iraqi civilians, including women and children, dead. The Iraq and US governments concluded the shooting was unprovoked. Blackwater argued their personnel came under fire and responded appropriately.

The charges consisted of 14 counts of manslaughter, 20 counts of attempted manslaughter and one count of firearms violation by using an assault gun in the course of committing a crime.

But Judge Ricardo Urbina of the US District Court in Washington ruled that prosecutors mishandled evidence and tossed out the case. The Iraqi government has urged the Obama administration to appeal the ruling.

'The State Department fully supported the Department of Justice in its investigation and prosecution of these individuals,' Crowley said.

'Whatever the case's ultimate outcome, we deeply regret the suffering and loss of life caused by the Nisour Square shootings, and we are fully committed to holding accountable persons who commit such crimes, whether at home or abroad,' he added.

The Iraqi government has banned Blackwater from operating in the country.