U.S. envoy says Islamic State branch in Libya greatest cause for concern

A man selling pastries walks past the rubble of damaged buildings in the rebel held al-Shaar neighborhood of Aleppo, Syria, February 10, 2016. REUTERS/Abdalrhman Ismail

WASHINGTON (Reuters) - The U.S. envoy to the coalition against Islamic State said on Wednesday that Russian airstrikes in Syria are boosting the militant group because of the toll they are taking on U.S.-backed opposition fighters.

"What Russia's doing is directly enabling ISIL," the envoy, Brett McGurk, told a hearing of the House of Representatives Foreign Affairs Committee, using an acronym for Islamic State.