A German court on Wednesday began hearing a multi-million-euro class action lawsuit by relatives of victims of a deadly air raid in Afghanistan called in by NATO's German command.
The September 2009 bombing by US planes near the northern Afghan city of Kunduz on two fuel tankers stolen by insurgents killed and wounded dozens of civilians, prompting outrage in Germany and a political scandal.
Germany's Bundestag lower house of parliament described the strike as "one of the most serious incidents involving the German military since the Second World War".
A total of 79 families are seeking 3.3 million euros ($4.3 million) over the bombing, calling it a gross violation of international law.
Wednesday's hearing at a court in the western city of Bonn focused on claims by a father seeking 40,000 euros after the death of two of his children and a widowed mother-of-six whose claim amounts to 50,000 euros.
The German government tried to have the case thrown out, arguing the air strike came under NATO command and thus could not be blamed on Berlin alone.
"The federal republic of Germany is not the right respondent," said the lawyer defending the government, Mark Zimmer.
"The conditions (for a lawsuit) have not been fulfilled."
The German government has already paid out around $430,000 to families affected by the raid which it stressed was not compensation but humanitarian aid.
However, presiding judge Heinz Sonnenberger agreed to hear the lawsuit, saying the case would hinge on whether the plaintiffs could prove state liability for the loss of life.
"We will have to review whether international humanitarian law has been violated," he said.
A lawyer for the plaintiffs, Peter Derleder, said he felt confident after the first day of the case in court.
"The court did not rule out a claim based on a violation of international law," he said. "There should have been a warning flight to put civilians on alert."
Germany is the third-largest contributor of troops to NATO's International Security Assistance Force (ISAF), behind the United States and Britain, with around 4,400 troops in Afghanistan.
The court will resume hearing the case on April 17.