Istanbul, Turkey - The first day of the Astana talks on the six-year-old Syrian war wrapped up without the participation of the armed opposition.

Mohamed Alloush, the head of the Syrian opposition delegation at the first round of talks, told Al Jazeera that the decision to boycott was taken because their demands were not being addressed.

"The Russians did not abide by their promises. They didn't release prisoners, they didn't stop the bombing, they didn't stop the forced displacement," Aloush said.

Abdul Majeed Barakat, political adviser to the Free Syrian Army (FSA) factions involved in the Turkey-backed Euphrates Shield Operation in northern Syria, told Al Jazeera that the opposition was not clear on what the plans were for this round of talks in Kazakhstan's capital - and Turkey didn't push it to attend.

"The Turks did not really encourage the participation [of the opposition]. They didn’t stop it, but they didn't encourage it either," said Barakat.

Commenting on the boycott, Russian Foreign Minister Sergey Lavrov said the reasons the opposition offered were "unconvincing". He said the no-show was "unexpected", and on Monday he talked with his Turkish counterpart, Mevlut Cavusoglu, about it.

"We have reason to believe that there is some kind of a misunderstanding. In any case, the Astana meeting will proceed along the way which was outlined in the UNSC resolution 2254," he told journalists at a press conference in Moscow.

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In Astana, Syrian government envoy Bashar al-Jaafari blamed Turkey for the opposition boycott.

"When one of the three guarantors breaks their commitment - and I mean Turkey - this means that Turkey must be the one that is asked about the non-attendance or participation of these armed groups," al-Jaafari said.

Turkey's delegation, headed by deputy undersecretary of the ministry of foreign affairs Sedat Onal, is attending the discussions, which are scheduled to end on Wednesday.

According to Emre Ersen, a lecturer at Marmara University's Department of Political Science and International Relations in Istanbul, the opposition boycott has to do with disagreements between Russia and Turkey on Syria.

"It is related to the current rift between Turkey and Russia regarding Manbij. They couldn't overcome their differences in the latest Putin and Erdogan meeting," Ersen told Al Jazeera.

Turkey's President Recep Tayyip Erdogan met with his Russian counterpart Vladimir Putin on March 10 in Moscow.

During the meeting, Erdogan made it clear that Turkey expected Russia to end ties with Kurdish armed groups such as the People Protection's Unit (YPG) that it considers a "terrorist" organisation.

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The US-backed Syrian Democratic Forces (SDF), which include the YPG, recently gave up territory in favour of Syrian government forces west of the city of Manbij, in northern Aleppo province.

Shortly after, Russia announced its presence in the city. US troops, which provide logistical support and training to the SDF, were also present in the Manbij area. SDF's withdrawal in favour of the Syrian forces effectively stopped the progress of Turkey’s Euphrates Shield Operation against Islamic State of Iraq and the Levant (ISIL).

According to Ersen, the refusal of the armed opposition to join the talks in Astana is a way for Ankara to suggest its dissatisfaction with the current situation in northern Syria. The move, however, could endanger the normalisation in Russian-Turkish relations.

"[The opposition's boycott] might create a problem for Russia in terms of its influence in the Syria peace process. Astana actually symbolises Russia's dominance in the Syrian question, because it excludes the United States," Ersen said.

"It is the Russian plan. If it fails, if it is undermined because of this, it will definitely create a bigger problem between Turkey and Russia."

The opposition's no-show at Astana came a week after the fourth round of negotiations in Geneva ended with almost no progress. A new round of talks in Switzerland is scheduled for March 23.