DEVELOPING -- U.N.-Arab League envoy Kofi Annan, the former U.N. secretary-general who has been trying to mediate the crisis in Syria, resigned from his position Wednesday.

United Nations Secretary General Ban Ki-Moon accepted Annan's resignation "with deep regret."

"Mr. Annan has informed me, and the Secretary-General of the League of Arab States, Mr. Nabil El Araby, of his intention not to renew his mandate when it expires on 31 August 2012," Ban Ki-Moon said in a statement. "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."

Annan's successor has not yet been appointed.