Lakhdar Brahimi will resign as the joint UN-Arab League envoy on Syria after a nearly two-year effort that failed to bring peace to the war-ravaged country, the UN secretary-general announced Tuesday, May 13, according to the Associated Press.

UN Secretary-General Ban Ki-Moon said Brahimi will step down May 31. He pledged to keep working to achieve peace.

When Brahimi took the job, replacing his longtime friend, former UN secretary-general Kofi Annan, he said it would be "an extremely complicated and very, very difficult mission."

Brahimi chaired two rounds of peace talks between opposition leaders and government officials in Geneva that ended without an agreement and even a way to ending the bloodshed.

The only achievement of the Geneva talks before they broke off in February was a week-long ceasefire in the central city of Homs to evacuate hundreds of civilians that have lived under a crippling army siege.

Assad's forces earlier this week took full control of Homs following a ceasefire agreement with the rebels that allowed more than 2,000 opposition fighters to leave the city, which had been dubbed the "capital of Syrian revolution."