A skydiving plane crashed Sunday in eastern France, killing all 11 people on board, local authorities said, in one of the country's deadliest ever light aircraft accidents.

The crash in the town of Tomblaine killed five instructors, five students, and the pilot, said Yves Seguy, the prefect of the Meurthe-et-Moselle department.

The students were a group of nurses, according to a source close to the case and confirmed by the head of Meurthe-et-Moselle's nursing council, Thierry Pechey.

"They were colleagues who had decided to go on a first skydiving jump, no doubt to unwind, as we're going through a difficult time with the heatwave," he said.

Mayor of the nearby city of Nancy, Mathieu Klein, said the victims "died in full view of their loved ones, who were preparing to film the tandem skydives." 

Medical and psychological support teams were caring for relatives of the victims who were present, as well as other witnesses, according to local authorities.

The aircraft, registered in Germany, crashed in a grassy area near the runway of the Nancy-Essey aerodrome, close to a residential area and two roads, an AFP journalist reported.

"It's tragic, but it could have been even worse," said Klein, noting the plane crashed "just a few meters from homes." 

Tomblaine mayor Herve Feron said the plane fell "in a completely unexplained manner ...during the ascent," describing it as crashing "straight down." 

The aircraft had been "chartered for the occasion, for the skydiving weekend, as is regularly done," he added.

The cause of the incident was not immediately clear and a technical investigation had been opened, said Amaury Lacote, deputy public prosecutor in the eastern city of Nancy.

Police urged people on the social media platform X to "strictly avoid" the area around the airport to allow emergency services access.

French Interior Minister Laurent Nunez and Transport Minister Philippe Tabarot are expected to visit the scene of the accident later this afternoon.