The United Nations’ chief mediator for Syria, Staffan de Mistura, said Wednesday that he would step down at the end of November, becoming the third diplomat to leave the job since Syria’s civil war began in 2011.
Mr. de Mistura announced his resignation as special envoy during a meeting of the Security Council after four years and four months in the role, at a time when the future of Syria is uncertain. His departure could complicate efforts to negotiate an end to the war as it is winding down.
While his predecessors left the job out of frustration, Mr. de Mistura, 71, said he was leaving for “purely personal reasons,” adding, “ I will definitely not say goodbye or engage in reflections today.”
The conflict, which began as a popular uprising in 2011 before degenerating into civil war, has killed hundreds of thousands of people and displaced millions.
The United Nations-backed peace process, the so-called Geneva talks, are the longest running attempt at peacemaking in Syria and have been convened eight times with no significant progress. While the talks have deadlocked, the Syrian government, with its Iranian and Russian allies, has nearly succeeded in defeating the opposition.
The futility of those talks led to the departures of Mr. de Mistura’s two predecessors, Kofi Annan, the former United Nations secretary general, and Lakhdar Brahimi, a veteran Algerian diplomat. Mr. Annan called the job “mission impossible.”
The Geneva process has been somewhat overtaken by Russia-led negotiations involving the Syrian government of President Bashar al-Assad, Russia, Turkey, and Iran. While most Syrian rebel groups have refused to participate, those talks did create a demilitarized zone in Idlib Province, the last major rebel-held area in Syria, an agreement which the rebels seem to be observing.
Opposition fighters pulled out the last of their heavy weapons from front-line positions in the province last week, possibly sparing the civilians there from the type of bloody government offensive seen elsewhere in the country.
Those Russia-led talks also created a framework to establish a committee to write a new Constitution for Syria, a goal Mr. di Mistura has pushed for.
Mr. di Mistura had previously served as a deputy foreign minister in the Italian government and as the head of the United Nations mission in Afghanistan.
His colleagues praised his work as envoy to Syria.
Jan Egeland, the Secretary General of the Norwegian Refugee Council, who worked closely with him, expressed admiration for his “herculean effort, every day, every night, every weekend” for four years trying to bring parties to the Syrian conflict to the negotiating table.
“It’s been the same uphill battle his predecessors faced, but against all the odds, there have been a number of achievements,” Mr. Egeland said.
He said that Mr. de Mistura had made the peace process more inclusive, bringing in civil society groups and women, and had also spoken bluntly about atrocities and abuse of civilians.
“It’s been one crisis and horror after another, from Homs to Aleppo, to Raqqa to Eastern Ghouta to Daraa and now Idlib,” Mr. Egeland said. “There never seems to be a good time to step down.”
Mr. di Mistura said he had not given up on the peace process, and that he would spend his last month in the job working to create a “credible and balanced” constitutional committee for Syria.
“A month can be a century in politics,” he said. “We will still have a very intense and, hopefully, fruitful month ahead. I am not laying down the charge until the last hour of the last day of my mandate.”