More British troops could be on their way to Afghanistan as part of a Nato plan to increase force numbers to help the country’s embattled government fight a resurgent Taliban.

International military officers have watched with alarm as Kabul’s territorial control has slipped to little more than half the war-racked nation, according to US estimates, amid accusations that Russia is supplying arms to the Taliban.

In an interview with a German newspaper, Jens Stoltenberg, Nato secretary general, said the “challenging” security situation meant the alliance was weighing a plan to increase the number of personnel in its Resolute Support mission beyond the current level of 13,000.

Nato will make its decision by June on any troop increase and on whether to lengthen deployments which currently run for a year, he was quoted by the Welt am Sonntag newspaper as saying.

He added that Nato could become more engaged in Jordan and Tunisia, calling both "islands of stability" in an unstable region.

The British deployment to Afghanistan amounts to about 500 personnel.

They are mostly deployed to provide security around the capital Kabul but also include special forces commandos.

The UK keeps troop levels under constant review in line with Nato needs but it is understand that the Ministry of Defence has not yet received any formal request for an increase.