ASTANA, Kazakhstan — Negotiators for the Syrian government and representatives of rebel factions traded accusations of terrorism after their first face-to-face meeting on Monday, as talks in Kazakhstan arranged by Russia and Turkey got off to a rocky start.

The gathering in Astana, the Kazakh capital, is the latest in a long line of diplomatic initiatives aimed at ending the nearly six-year-old Syrian war, which has killed hundreds of thousands of people and displaced half the country’s population.

The talks are expected to focus on shoring up a shaky cease-fire declared last month and not on reaching a larger political settlement, and Syria’s bitter divide was on vivid display as the delegates emerged from a closed, hour-long session.

Syria’s U.N. envoy Bashar Ja’afari said the opposition delegation represented “terrorist armed groups,” and denounced the opening address delivered by the chief rebel negotiator, calling it “provocative” and “insolent.”

The head of the rebel delegation, Mohammad Alloush, had described Syrian President Bashar Assad’s government as a “terrorist” entity, and called for armed groups fighting alongside it, including the Lebanese Hezbollah, to be placed on a global list of terrorist organizations, according to a video leaked by opposition delegates.

“The presence of foreign militias invited by the regime, most notably the Lebanese Hezbollah and the Iraqi Hezbollah …  contributes to the continuation of bloodshed and obstructs any opportunity for a cease-fire,” Alloush said in the video.

He added that such outfits were no different than the Islamic State group, which is excluded from the cease-fire.

U.N. envoy Staffan de Mistura is mediating the talks, which are to be followed by more negotiations in Geneva next month. This time last year, he was shuttling between government and opposition delegations seated in separate rooms in Geneva, in talks brokered by the U.S. and Russia that led nowhere.

The new U.S. administration is not directly involved in the current talks, because of the “immediate demands of the transition,” the State Department said Saturday.