Two French pilots died on Wednesday after their Rafale jets collided in mid-air in eastern France, President Emmanuel Macron said, in a rare accident involving the cutting-edge military aircraft.

One pilot ejected following the crash over northeastern France, but authorities had launched a desperate search for a missing instructor and a student pilot on the second jet.

"We learn with sadness the death of Captain Sebastien Mabire and Lieutenant Matthis Laurens in an air accident in a Rafale training mission," Macron posted on X, formerly Twitter.

"The nation shares the grief of their families and brothers in arms at Air Base 113 in Saint-Dizier" in eastern France, he added.

"One of the pilots was found safe and sound," Defence Minister Sebastien Lecornu said earlier on X.

It was not immediately clear what caused the collision that authorities said occurred over Colombey-les-Belles, a town in northeastern France.

"The military authorities will report on the causes of the accident," said the local prefecture.

The supersonic Rafale "multi-role" fighter -- used to hunt enemy planes, strike ground and sea targets, carry out reconnaissance and even carry France's nuclear warheads -- has become a bestseller for the French arms industry.

Accidents involving Rafale jets are rare.

- 'Strange noise' -

"We heard a loud noise, around 12:30pm (1030 GMT)," Patrice Bonneaux, deputy mayor of Colombey-les-Belles, told AFP.

It was not the usual sonic boom of a fighter jet breaking the sound barrier, he said. "It was a strange noise, a percussive sound".

"I assumed that two planes had collided, but we didn't believe it," he said, adding that a road bordering a nearby forest had been cordoned off.

In December 2007, a Rafale jet crashed near Neuvic in southwestern France. Investigators concluded that the pilot had become disorientated.

That was believed to be the first crash of a Rafale.

In September 2009, two Rafale aircraft went down as they flew back to the aircraft carrier Charles de Gaulle off the coast of Perpignan after completing a test flight. One pilot died.

France has sold the Rafale to Egypt, India, Greece, Indonesia, Croatia, Qatar and United Arab Emirates.

Lecornu said in January that France had ordered 42 new Rafale fighter jets, with the first to be delivered in 2027. The French military has now ordered more than 230 Rafales since the jet went into service.

Macron has urged defence manufacturers to boost production and innovation as Europe seeks to increase arms supplies to buttress Ukraine, which has been struggling to fight off Russia's invasion, now in its third year.