Russia is supporting and supplying arms to the Taliban, Gen John Nicholson, the head of US forces in Afghanistan, told the BBC in an interview.

Nicholson, during the interview published on Friday, said he had seen "destabilising activity by the Russians", alleging that Russian weapons were smuggled across the Tajik border to the Taliban. He, however, did not say in what quantity.

"We see a narrative that's being used that grossly exaggerates the number of Isis [Islamic State group] fighters here," Gen Nicholson was quoted as saying by the BBC. "This narrative then is used as a justification for the Russians to legitimise the actions of Taliban and provide some degree of support to the Taliban."

"We've had stories written by the Taliban that have appeared in the media about financial support provided by the enemy," he added. "We've had weapons brought to this headquarters and given to us by Afghan leaders who said, 'This was given by the Russians to the Taliban' — we know that the Russians are involved."

Russian officials have previously denied providing aid to the militants, saying that their limited contacts were aimed at bringing the Taliban to the negotiating table.

Last year in March, the US media had reported that Russia was providing political legitimacy and military supplies to the Taliban in Afghanistan.

“American military officers see a growing Russian effort to bolster the Taliban’s legitimacy and undercut (the US and) Nato’s military effort there,” CNN had reported.

A spokesperson for the Russian foreign ministry had rejected the claims as “absolutely false”, alleging that such announcements were “designed to justify the failure of the American political and military campaigns” in Afghanistan.