"The first troops from the British Chinook deployment, which will comprise three heavy transport helicopters and will be deployed in Gao ( northern Mali) have arrived," armed forces spokesman Colonel Patrik Steiger said.

The advance party from a contingent that will be in place by the end of the summer arrived in Niamey, the capital of Niger, Mali's neighbour to the east, Steiger added.

In January, Prime Minister Theresa May promised French President Emmanuel Macron that Britain would step up its support for France's Barkhane mission, which has been pursuing jihadist groups across the arid Sahel region since 2014.

May said that although Britain was preparing to leave the EU, "this does not mean that the UK is leaving Europe," stressing Britain's commitment to its cooperation with France in the area of defence.

Until now Britain's contribution to France's operations in the Sahel region had been limited to the regular use of a C-17 troop transporter.

Steiger said the US-made Chinook helicopters, which can carry about 40 troops, would be "very useful" for the mobility of the Barkhane force.

In 2013, the French military intervened in Mali to help rout Islamic extremists linked to Al-Qaeda from the country's desert north.

Within days French-backed forces had recaptured all of northern Mali's towns but the jihadists have continued to carry out attacks from their rear bases in the desert, while stepping up their operations in neighbouring countries.