A group of 160 Chadian troops from the United Nations peacekeeping force in Mali have deserted their posts in a dispute over pay and conditions, a military source and the soldiers themselves told AFP on Tuesday.

A Chadian army captain claiming to be the leader of the deserters told AFP by telephone his men had left their posts in the northeastern town of Tessalit overnight from Monday to Tuesday and were heading to the city of Gao.

"There are 160 of us. We left the Amachache camp in Tessalit to claim better living conditions and demand our wages too," said the officer who did not wish to be named.

"We have been in Mali for nine months and many of us haven't been paid -- that is not good."

Asked whether the deserters were armed, the officer said: "A soldier always has his weapon by his side."

Speaking on condition of anonymity, an officer from MINUSMA -- the UN peacekeeping mission in Mali -- confirmed that soldiers had deserted, saying "more than 150 soldiers" had left without permission and would be met in Gao by a Chadian military delegation.

The 2,000 Chadian soldiers of the African-led International Support Mission in Mali (AFISMA) were at the forefront of a French-led military intervention launched in January to oust Islamist rebels who had taken over northern Mali in the chaos following a coup.

Chad lost at least 38 men in battle, with the heaviest fighting taking place in the northeastern Ifoghas mountains.

The UN peacekeeping force, expected to reach a strength of 12,600, replaced AFISMA in July.