Iraq has denounced a US judge for dropping all charges against five guards from US security firm Blackwater accused of killing 14 Iraqi civilians in 2007.

Human Rights Minister Wejdan Mikhail said she was “astonished”.

She has summoned the US ambassador in Baghdad for an explanation.

The US judge dismissed the charges saying prosecutors had used statements made by the defendants under immunity. The minister says the guards had opened fire at unarmed civilians.

The bloodbath prompted widespread outrage in Iraq.

US private security guards have been accused of systematic abuses. Both the Iraqi and US governments have since banned Blackwater from operating in Iraq. Blackwater recently changed its name to Xe.