A British surveillance plane took off on Friday to support French military operations against Al Qaeda-linked rebels in Mali, the Ministry of Defence said.

The Sentinel plane lifted off from RAF Waddington airbase in eastern England "to an airbase in Africa, in support of French military operations in Mali", a spokesman said, adding it will be based in neighbouring Senegal.

Britain has already contributed two C-17 transport planes to France to airlift military equipment to Mali, although only one of the giant planes is still being used.

Defence Minister Philip Hammond said the Sentinel had been used in the conflict in Libya last year and is currently being deployed to support British forces fighting insurgents in Afghanistan.

"Following discussions with the French, we have now decided to deploy Sentinel, a surveillance capability that has proved its worth in Libya and on an ongoing basis for counter-insurgency operations in Afghanistan," he said.

Prime Minister David Cameron has given France's military intervention his full backing, but has stressed that Britain is not considering sending troops to the West African country.

The Sentinel can observe what is happening on the ground and feed information to military commanders.

French and Malian troops on Friday advanced on the key Islamist stronghold of Gao after recapturing the northern town of Hombori as the military operation moved into a third week.