Four Polish soldiers face a new war crimes trial after Warsaw's supreme court on Wednesday overturned their acquittal of the killing of Afghan civilians, including women and children, in 2007.

The court however confirmed the acquittal of three others, including a base commander, in the case marking the first ever court martial for war crimes involving Polish troops fighting abroad.

"The prosecutor's appeal is in part justified," Judge Wieslaw Blus told Poland's highest court.

"The court has overturned the ruling and is forwarding the case for a new review."

The judge said the June 2011 acquittal that he had decided to strike down had failed to consider all the evidence concerning four of the accused.

He identified them as second lieutenant Lukasz Bywalec, warrant officer Andrzej Osiecki, master corporal Tomasz Borysiewicz and private Damian Ligocki.

The four had given "contradictory" accounts of the incident in which six Afghan civilians died including two women, three children and a man while several others were wounded, said the judge.

"Their guilt or their innocence will be determined by an independent court," Justice Blus said.

Welcoming the verdict, Second Lieutenant Andrzej Oscieki -- one of the four soldiers facing a retrial -- told reporters the "ruling does not assume our guilt."

"The most important is that three of us have been completely acquitted and this makes me very happy," he said, as soldiers implicated in the case exchanged handshakes.

In June last year, a Polish court had cleared the seven soldiers of war crimes over the deaths of the six civilians on August 16, 2007 in the village of Nangar Khel. It said there was no evidence to suggest the troops had intended to attack civilians.

Prosecutors however insisted that evidence that suggested the deaths were "a deliberate act" had been overlooked and launched an appeal.

At the original trial, prosecutors had sought prison sentences ranging from five to 12 years for the accused.

The soldiers, members of Poland's contingent in NATO's International Security Assistance Force (ISAF), opened fire with mortars and automatic weapons on the village in the mountainous southeastern Paktika province. They said they had been responding to an earlier attack by Taliban rebels.

Prosecutors had argued that the soldiers breached laws governing the conduct of war -- notably the 1907 Fourth Hague Convention and the 1949 Fourth Geneva Convention, governing the treatment of civilians in a conflict zone.

The soldiers pleaded not guilty, claiming that they were responding to a Taliban attack and that the deaths had resulted from faulty mortar equipment.

But prosecutors had alleged the deaths occurred several hours after the Poles had responded to an attack on a separate patrol.

Ex-communist Poland, which joined NATO in 1999, has some 2,500 troops deployed with the Western defence alliance's mission fighting a Taliban insurgency.

Following talks with Afghan President Hamid Karzai last week, Poland's President Bronislaw Komorowski said Polish troops would remain in Afghanistan until the NATO deadline of end-2014.

The US-led NATO force has 130,000 troops fighting the Taliban, who were toppled from power in a US-led invasion in 2001.

There has been pressure in some European countries for an early withdrawal after NATO troops were targeted by their Afghan colleagues.