Kofi Annan is quitting his post as the UN and Arab League envoy to Syria, UN Secretary General Ban Ki-moon said on Thursday.
Ban said in a statement Annan had decided not to renew his mandate when it expires on August 31.
“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.
Annan was appointed the UN and Arab League envoy to Syria in February and authored a six-point peace plan aimed at ending the Syrian conflict.
Ban said Annan deserved "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.”
The UN chief said he was negotiating a successor to Annan with Arab League Secretary General Nabil Elaraby.
Ban pointed out that the “spiral of violence in Syria is continuing,” and that both the government of President Bashar al-Assad and the opposition forces “continue to demonstrate their determination to rely on ever-increasing violence.”
“In addition, the persistent divisions within the Security Council have themselves become an obstacle to diplomacy, making the work of any mediator vastly more difficult,” he added.
He stressed, however, that the United Nations remained committed to “pursue through diplomacy an end to the violence and a Syrian-led solution that meets the legitimate democratic aspirations of its people."
Moscow regrets Annan’s decision to leave the post, Vitaly Churkin, Russia’s envoy to the United Nations, told journalists in New York.
“We were strongly supporting Kofi Annan’s efforts,” Churkin said.
He said, however, that he was “inspired” by the fact that the candidacy to replace Annan was already being negotiated, and expressed hope that the weeks preceding the end of Annan’s mandate will be used “as effective as possible” to achieve the goal of political settlement in Syria.
The conflict, which began in March 2011, has already claimed up to 20,000 lives, according to Syrian activists, and the international community has failed to persuade the Assad government and opposition forces to stop fighting and begin dialogue.