On May 13, Lakhdar Brahimi, U.N. special envoy to Syria, announced that he was quitting his position as lead mediator of the Syrian conflict due to frustration with a lack of progress. The same day, a French diplomat said the Syrian government had used chemical weapons more than 12 times after signing a treaty banning the weapons, according to the New York Times.

“It’s very sad that I leave this position and leave Syria behind in such a bad state,” Brahimi told reporters.

He was the second high-level mediator to abandon the conflict. In 2012, former United Nations Secretary-General Kofi Annan gave up his efforts to negotiate an end to the civil war after Syrian President Bashar al-Assad’s government failed to implement the six-point plan that Annan had negotiated between the government and opposition leaders.