Acting in conjunction with Chad's government, French Mirage 2000 jets targeted the convoy again on Tuesday and Wednesday, destroying about 20 of roughly 50 pickup trucks the rebels started out with, the armed forces said in a statement.

Chadian forces had already tried to stop the column with airstrikes of its own on Friday and Saturday, before asking France for warning passes and then strikes that were carried out Sunday.

"The armed column... did not respond to the warnings and strikes," the army said, prompting the fresh strikes which were carried out from a base near N'Djamena with the support of a Reaper drone.

It did not identify the rebels, but a spokesman for Chad's most active rebel group said this week the raid had targeted its men, and warned of reprisals.

An armed forces spokesman said this week the convoy had crossed 400 kilometres (250 miles) of Chadian territory before being halted "between Tibesti and Ennedi" in the northwest.

Chad, a vast and mostly desert country with more than 200 ethnic groups, has suffered repeated coups and crises since it gained independence from France in 1960.

Under President Idriss Deby, a former head of the armed forces, the country has taken a leading role in the fight against jihadism in the Sahel region.

It is part of a West African coalition fighting the Boko Haram insurgency, and a member of the French-backed G5 Sahel anti-terror alliance, which also includes Burkina Faso, Mali, Mauritania, and Niger.

The latest incursion follows several recent air strikes by the Chadian air force against Libya-based rebels in the far north.