Syrian Kurdish forces have taken near complete control of Hasaka city as a ceasefire ended a week of fighting with the government, consolidating the Kurds' grip on Syria's northeast as Turkey increases its efforts to check their influence.
The Kurdish YPG militia, a critical part of the US-backed campaign against Islamic State, already controls swathes of northern Syria where Kurdish groups have established de facto autonomy since the start of the Syria war in 2011.
Their growing sway has alarmed Turkey, which is fighting an insurgency among its own Kurdish minority.
Syrian rebels backed by Turkey said they were in the final stages of preparing an assault from Turkish territory on the Islamic State-held Syrian border town of Jarablus, aiming to pre-empt any YPG attempt to take it.
"We will give every kind of support to the Jarablus operation. This is important for our own security," Turkish Foreign Minister Mevlut Cavusoglu told a news conference on Tuesday.
The battle over Hasaka marked the most violent confrontation between the YPG and Damascus in more than five years of civil war, with the Syrian air force used against the US-backed Kurdish forces for the first time last week.
On Tuesday Hasaka's remaining government officials were confined to a few buildings known as the security quarter, while the rest of the city was under Kurdish control. The Kurds held around 70 percent of Hasaka prior to the latest fighting.
The terms of the ceasefire that came into effect at 2pm local time on Tuesday included the withdrawal of the Syrian army and allied militia from Hasaka city, Kurdish officials said.
Turkey is focused on preventing the YPG or its allies building on recent advances against Islamic State by capturing the town of Jarablus.
Turkey has been shelling Islamic State positions in Jarablus as part of an effort to help allied Syrian rebels secure it. Rebel sources say they have been mobilising in Turkey, ready to cross into Jarablus.