Kurdish-controlled areas of northern Syria are expected to declare a federal system, a move likely to further complicate peace talks in Geneva aimed at ending more than five years of war.
Russia pulled more warplanes out of Syria, a new delivery of humanitarian aid reached northern Aleppo province and UN mediator Staffan de Mistura named a Russian academic to his team of advisers in a nod to Moscow's importance in brokering an end to the fighting.
But despite a more than two-week-old "cessation of hostilities" and Russian President Vladimir Putin's decision to pull out some of his country's forces that have tipped the balance of the war in Syrian President Bashar al-Assad's favour, any hopes of a breakthrough at the peace talks in Geneva remain slim.
Russia's defence ministry on Wednesday (local time) reported 10 new ceasefire violations and the Kurds, after being excluded from the talks in Geneva, appeared to be taking matters into their own hands by drawing up plans to combine three Kurdish-led areas of northern Syrian into a federal arrangement.
The three areas already have de facto autonomy and while it was unclear what the new system would entail, there was no indication it would involve a separation from Syria.
The new arrangement, which a conference in the Kurdish-controlled town of Rmeilan agreed would be announced on Thursday, would alarm neighbouring Turkey, which fears growing Kurdish sway in Syria is fuelling separatism among its own minority Kurds.
"Syria's national unity and territorial integrity is fundamental for us. Outside of this, unilateral decisions cannot have validity," a Turkish foreign ministry official said.
The US said on Wednesday it opposed Syrian Kurds forming an autonomous region in northern Syria, but could accept such an arrangement if the Syrians collectively agreed on it.
The Syrian Kurdish YPG militia have been an important ally in the US-led military campaign against Islamic State in Syria, and this has been a point of friction between the US and its NATO ally Turkey.
However, Bashar Ja'afari, head of the Syrian delegation in Geneva, rejected any talk of a federal model for Syria and ruled out direct talks with the main opposition delegation.
The main opposition group's chief negotiator, Mohamad Alloush, said it had not yet decided whether it would hold direct negotiations with "the regime delegation".