The top U.S. general in Europe told lawmakers Thursday that Russia and the Taliban are growing increasingly close, suggesting that the Kremlin might even be supplying the insurgent group.

Army Gen. Curtis Scaparrotti, who is also the Supreme Allied Commander of the North Atlantic Treaty Organization, did not elaborate to the Senate Armed Services Committee on what type of equipment the Taliban might have received or when.

Any type of material support, however, would be a significant escalation of Russia’s involvement with the Taliban; it has said in the past that it maintains only limited communication with the group.

“I’ve seen the influence of Russia of late, increased influence in terms of association and perhaps even supply to the Taliban,” Scaparrotti said.

Much to the chagrin of U.S. officials and military officers, Russia has justified its communications with the Taliban by saying the insurgent group is fighting the Islamic State in Afghanistan, not the U.S.-backed Afghan government.

Army Gen. John Nicholson, the commander of U.S. forces in Afghanistan, has decried Russia’s contact with the Taliban, saying that it has given cover to a group that has worked for years to undermine the United States and the government in Kabul. Russia fought its own bloody war of attrition in Afghanistan in the 1980s, pulling out after suffering heavy losses from U.S.-supplied insurgents.

“This public legitimacy that Russia lends to the Taliban is not based on fact,” Nicholson told reporters in December.

The Russian Foreign Ministry on Friday dismissed the allegations, however, calling it “a lie” and an attempt by Washington to justify its policy failures in Afghanistan, the RIA news agency reported.

On Thursday, the district center of Sangin in Afghanistan’s restive south province of Helmand was overrun by the Taliban after months of heavy fighting with Afghan forces backed by U.S. air support. In recent months, the Taliban has steadily increased control over large swaths of the country, prompting Nicholson to suggest that thousands more troops are needed to help better train the Afghan military and reverse the “stalemate” in the country. His assessment was subsequently echoed by Gen. Joseph Votel, the head of U.S. Central Command.

Currently, about 5,000 NATO troops are in the country, in addition to the 8,400-strong American presence. U.S. forces primarily support the Afghans through training and airstrikes while small contingents of Special Operations forces continue to conduct counterterrorism missions against the network of terrorist groups still located in the country.