UNITED NATIONS (Reuters) – The U.N.-Arab League mediator in the Syria conflict, Lakhdar Brahimi, has agreed to stay on despite his frustration at the international deadlock that has prevented U.N. action to halt the two-year-old civil war, the United Nations said on Thursday.

A dispute over Syria between Russia, which supports and provides weapons to the government of President Bashar al-Assad, and the United States, which says Assad must go and backs the rebels, has left the U.N. Security Council paralyzed.