A notorious Islamist militia leader known as "Red Beard" has been killed in French missile strikes in north-eastern Mali, a senior Malian army officer told AFP.

Omar Ould Hamaha was a commander of the Movement for Oneness and Jihad in West Africa (MUJAO) and Al-Qaeda in the Islamic Maghreb (AQIM), armed groups which occupied northern Mali for almost ten months in 2012.

"Omar Ould Hamaha, the terrorist of Malian nationality, is one of ten terrorists killed last week by French planes," the officer said late on Thursday.

Hamaha's death was confirmed by a regional security source who said he was killed "with weapons in hand".

French Defence Minister Jean-Yves Le Drian said last week as many as 12 AQIM fighters had been killed in a counter-terrorism operation by French forces between March 4 and 5.

The AQIM fighters were spotted in the Amettetai Valley, in the Kidal region, by French forces operating the US-made Reaper drones, Drian said.

A former lieutenant of one of the main jihadist chiefs in the Sahel, Algerian Mokhtar Belmokhtar, Hamaha was wanted by the Malian government and the United States, which offered $3 million (2.2 million euros) for information leading to his capture.

Hamaha, nicknamed "Red Beard" because he regularly died his facial hair with henna, was implicated in the April 2012 abduction of Algerian diplomats in Gao, Mali's largest northern city, claimed by MUJAO.

Mali was thrown into chaos in 2012 when Tuareg separatist rebels launched an offensive in the northern desert helped by AQIM and MUJAO, after the country's president was toppled in a coup.

The Islamists took control of northern Mali, ruling it under a brutal version of Islamic law until former colonial ruler France sent in troops to flush them out in January 2013.

UN peacekeepers took over security in July last year from the Pan-African AFISMA military mission, which had been supporting the French troops.

France is winding down its deployment from a peak of around 5,000 soldiers but is to keep 1,000 troops in Mali beyond the spring.