Lebanese Muslim group Hezbollah welcomed Russia ' s military buildup in Syria in support of common ally President Bashar al - Assad, saying it was the failure of a U. S. - led campaign against Islamic State that had forced Moscow ' s hand. Hezbollah leader Hassan Nasrallah said in a three-hour interview with the group's al-Manar TV that increased Russian support for Assad included highly advanced weapons systems, warplanes and helicopters. Russia has stepped up its military involvement in Syria while pressing for Damascus to be included in international efforts to fight Islamic State, a demand Washington rejects. By raising the stakes in Syria's four-year conflict, Moscow has prompted its Cold War foe to expand diplomatic channels with it. Nasrallah said Washington's own campaign against IS, based on air strikes by a U.S.-led coalition and training so-called moderate Syrian rebels to fight on the ground, had been a "devastating failure". "The failure of America and the international coalition to bring defeat to Daesh was one of the reasons which called or pushed Russia to also come, and to get directly involved," he said. "We welcome any force which intervenes and supports the front in Syria, because through its participation, it will contribute to pushing away the major dangers that are threatening Syria and the region."