Kofi Annan is quitting as UN-Arab League envoy for Syria after battling to persuade President Bashar al-Assad to accept a peace plan, the UN said Thursday.
UN leader Ban Ki-moon announced "with deep regret," that Annan had tendered his resignation, as the Syrian civil war spiraled further out of control.
The UN and Arab League named Annan, a Nobel Peace prize winning former UN secretary general, as its envoy on the Syria conflict on February 23. Assad agreed a six-point peace plan with Annan but has never carried it out.
"I wish to express my deepest gratitude to Mr Annan for the determined and courageous efforts he has made as the Joint Special Envoy for Syria," Ban said in a statement.
"Kofi Annan deserves our profound admiration for the selfless way in which he has put his formidable skills and prestige to this most difficult and potentially thankless of assignments," Ban added.
The statement added that Annan had said he would not renew his mandate when it expires on August 31. Ban said that he was in discussions with the Arab League on naming a successor.