The central African country in late November abruptly ended military cooperation with its former colonial ruler, and French troops began leaving the country in late December.

"Today... marks the handover of the Abeche base," Defence Minister Issaka Malloua Djamouss said during an official ceremony.

He called it a key step "leading to the final and total withdrawal of this army in our country".

Around 100 troops left the Abeche base on Saturday, after equipment convoys departed Friday evening.

The French army had around 1,000 personnel in Chad.

Djamouss added that the January 31 deadline for France to remove forces for good was "imperative", "irreversible" and "non-negotiable".

French soldiers and fighter aircraft have been stationed in Chad almost continuously since the country's independence in 1960, helping to train the Chadian military.

The planes also provided air support that proved crucial on several occasions in stopping rebels moving to seize power.

Mid-December, the jets were the first to go, followed by a contingent of 120 soldiers and the handover of the Faya base in northern Chad.

- 'Friendship remains' -

"Partnerships evolve but the friendship remains between our two nations, as does the solidarity between two sovereign nations that will continue to move forward side by side as they always have," French embassy representative Fabien Talon said at the event.

The central African country, one of the poorest in the world, was the last Sahel nation to host French troops.

Paris at one point had deployed more than 5,000 soldiers as part of its anti-jihadist Barkhane operation.

Chad had been a key link in France's military presence in Africa and its last foothold in the wider Sahel region after the forced withdrawal of French troops from Mali, Burkina Faso and Niger in the wake of military coups.

The military authorities in Mali, Burkina Faso and Niger have pivoted towards Russia in recent years.

Chad's leader General Mahamat Idriss Deby Itno has also sought closer ties with Moscow in recent months, but talks to strengthen economic cooperation have yet to bear concrete results.

Deby described the agreement as "completely obsolete" and no longer aligned with the "political and geostrategic realities of our time".

His election in May brought an end to a three-year political transition triggered by his father's death in clashes with rebels in 2021.

Longtime ruler Idriss Deby Itno had received support from the French army to quell rebel offensives in 2008 and 2019.