Russia is supporting and even supplying arms to the Taliban, the head of US forces in Afghanistan has told the BBC.
In an exclusive interview, Gen John Nicholson said he'd seen "destabilising activity by the Russians."
He said Russian weapons were smuggled across the Tajik border to the Taliban, but could not say in what quantity. Russia has denied such US allegations in the past, citing a lack of evidence.
But the new claims come at a sensitive time in Russia's ties with Nato powers.
Britain and Russia are locked in a dispute over claims that Russia was behind an attack on a former Russian spy and his daughter on UK soil using a deadly nerve agent.
Meanwhile a US Congressional Intelligence Committee has just published a report concluding that Russian provocateurs meddled in the 2016 election.