The US Justice Department is considering charging a former Blackwater Worldwide security guard with murder over his alleged role in a 2007 massacre of unarmed civilians in Baghdad, a federal prosecutor said on Wednesday.

The Justice Department is weighing "all available options" against Nicholas Slatten including first-degree murder, Assistant US Attorney Anthony Asuncion said at a hearing in federal court in Washington.

Three other former Blackwater security guards face manslaughter charges in connection with the September 16, 2007 shootings at Nisur Square in Baghdad, in which 17 civilians were killed and more than a dozen others wounded.

Slatten had faced similar charges, but a federal appeals court earlier this month effectively ended the case against him, raising questions about whether prosecutors would continue to pursue him.

In court documents filed in March, prosecutors said they planned to show at trial that Slatten fired the first shots at Nisur Square, and that he had harbored "deep hostility" to Iraqi civilians.

He told people he wanted to "kill as many Iraqis as he could as 'payback for 9/11,'" and boasted of killing an old Iraqi woman who had a knife in her hand for chopping vegetables, prosecutors said.

The massacre, coming in the fourth year of the Iraq war, outraged Iraqis and further strained US-Iraqi ties.

Reuters