MOSCOW (AFP) - Russia said on Wednesday the United States had renounced its "co-sponsor" role in negotiating peace in Syria by closing down the Syrian embassy in Washington.

"Our American partners in essence are depriving themselves of the role of co-sponsor of the process of political regulation in Syria and willy-nilly playing into the hands of the hard-core Syrian opposition," the foreign ministry said in a statement after Washington on Tuesday closed down the embassy, citing the illegitimacy of President Bashar al-Assad's regime.