UN Special Envoy of the Secretary-General for Syria, Staffan de Mistura, gives a press conference.

The United Nations special envoy for Syria concluded Friday a marathon round of talks in Geneva with an agreement from the conflicting parties to pursue further talks on a political transition to end the six-year war.

For nine days, seasoned diplomat Staffan De Mistura engaged in day-to-night proxy talks with a delegation representing the government of Syrian President Bashar al-Assad and three opposition groups that only converged for the opening ceremony.

Speaking to reporters after another long day of meetings, the envoy called the round of talks “substantive” and said the parties had agreed to return later in March to discuss four points – governance, constitution, elections and counter-terrorism.

“The train is ready, it’s in the station, it’s warming up its engine,” he said. “It just needs an accelerator.”

Setting the agenda proved a delicate task in this round of talks, dubbed Geneva 4, which aimed to restore hope for a negotiated solution to a conflict that has raged for six years and claimed, by most counts, nearly half a millions lives.

De Mistura said that after a 10-month pause, the talks were unavoidably dominated by procedure, but he credited all sides for also addressing issues of substance. He noted that Damascus placed emphasis on terrorism and the opposition on a political transition.

He said all parties understood they were working toward implementation of a UN Security Council framework that sets out a “clear timetable” to draft a new constitution for Syria within 12 months and for free and fair elections to be held within 18 months.

But, the envoy warned, there are “people in Syria and outside who still believe there is a military option or a military solution.”

“That is fantasy,” he said, adding that the United Nations would work in the coming weeks and months to settle the conflict.

De Mistura said the Geneva talks had the support of key regional player Turkey, which supports the opposition, as well as the allies of Damascus, Russia and Iran. The three countries are the guarantors of a cessation of hostilities agreement mediated in Astana, the capital of Kazakstan.

The talks in Astana, like those in Geneva, are expected to continue. De Mistura said the efforts on these two fronts were complementary, with cease-fires leading to productive talks and productive talks in turn helping maintain cease-fires.

“If we don’t have productive talks, (the) cease-fire won’t last,” he said. “We are really working hand in hand but there are two hands.”

The head of the Syrian government delegation, Bashar al-Jaafari, met with De Mistura on Friday but made no statements. The three opposition delegations also held separate meetings with the U.N. envoy.

The opposition groups came together and faced the Damascus delegation only at the opening ceremony, a thoughtful moment rich in symbolism that could not be repeated after nearly 10 days of tense talks.

Despite periodic displays of division, Western diplomats and analysts who had come to shepherd the opposition through the tricky process credited the motley crew of political dissidents and military commanders for holding their ground.

As usual, the parties provoked and needled each other through press statements, but they didn’t walk out. The bar was set so low by De Mistura, who started the talks saying he expected no breakthroughs, that just keeping everyone at the table was viewed as an achievement.

“This is a war of six years where people were not even looking at each other. They were just fighting each other,” De Mistura noted.

He said his team had presented all delegations a paper outlining 12 different points, summarizing the commonalities shared by “all those who care about Syria.”

Since the last round of talks in Geneva, the Syrian opposition lost control of the strategic city of Aleppo. Western diplomats said they understand that the United Nations represents their best shot at a political transition, however slowly the process proceeds.

The commanders of armed opposition groups making their first appearance in Geneva left largely disappointed.

“When it comes to things on the ground, relating to the cease-fire, the fate of detainees, the besieged areas, I don’t think there is any progress,” Major Issam al-Rais, spokesman for the Southern Front, told The Associated Press.

He and other commanders nonetheless expressed hope for a political solution, but had no illusions that any agreement would require the support of Russia to become a reality in the absence of a clear position on Syria by the new US administration.

“We accepted to enter an open-ended political process,” al-Rais said.