Russian Foreign Minister Sergei Lavrov attends a news conference after a meeting with Lamberto Zannier, Secretary General of the Organisation for Security and Cooperation in Europe (OSCE), in Moscow, Russia, April 25, 2017. REUTERS/Maxim Shemetov

MOSCOW (Reuters) - Russian Foreign Minister Sergei Lavrov said on Tuesday that a U.S. allegation Moscow was supplying arms to Taliban insurgents in Afghanistan was unsubstantiated.

The head of U.S. and international forces in Afghanistan said on Monday he was “not refuting” reports that Russia was providing support, including weapons, to the Taliban.