Syria's government and Kurdish forces on Saturday extended their truce by 15 days, with Damascus saying it was to support the US transfer of ISIS group detainees from Syria to Iraq.
Several sources had earlier told AFP the truce would be prolonged, with a Syrian official in Damascus citing the same reason.
In a statement, the Syrian defense ministry said the 15-day extension would take effect at 11pm (2000 GMT) on Saturday.
"The extension of the ceasefire comes in support of the American operation to transfer ISIS detainees from SDF prisons to Iraq," the statement added, referring to the Kurdish-led Syrian Democratic Forces.
The SDF also confirmed the extension, saying it was reached "through international mediation, while dialogue with Damascus continues".
"Our forces affirm their commitment to the agreement and their dedication to respecting it, which contributes to de-escalation, the protection of civilians, and the creation of the necessary conditions for stability," it said in a statement.
Damascus and the SDF had initially agreed to a four-day ceasefire on Tuesday after Kurdish forces relinquished swathes of territory to government troops, who also sent reinforcements to a Kurdish stronghold in the northeast.
Three sources, including a Kurdish source and a Syrian official in Damascus, had told AFP earlier on Saturday that the ceasefire would be extended.
- ISIS transfer -
After the SDF lost large areas to government forces, Washington said it would transfer 7,000 ISIS detainees to prisons in Iraq.
Europeans were among the 150 senior ISIS detainees who were the first to be transferred on Wednesday, and two Iraqi officials told AFP that a second batch of "up to 1,000 ISIS detainees" were being sent on Saturday.
Turkish Foreign Minister Hakan Fidan, whose country is a key backer of Damascus but hostile to the SDF, had said during a TV interview Friday that in light of the ISIS prisoner transfers, "extending the ceasefire for a while longer might be considered".
The transfer is expected to take several days.
ISIS swept across Syria and Iraq in 2014, committing massacres and other atrocities before ultimately being territorially defeated by the SDF and a US-led coalition.
The truce between Damascus and the Kurds is part of a new understanding over Kurdish-majority areas in Hasakeh province and a broader deal to integrate the Kurds' administration into the state.
Syrian President Ahmed al-Sharaa's opposition forces toppled longtime ruler Bashar al-Assad in 2024.
The new authorities are seeking to extend state control across Syria, resetting international ties including with the United States, now a key ally.
The Kurdish source said the SDF submitted a proposal to the authorities through US envoy Tom Barrack that would have the government managing border crossings -- a key Damascus demand.
It also proposes that Damascus would "allocate part of the economic resources -- particularly revenue from border crossings and oil -- to the Kurdish-majority areas", the source added.
Earlier this month, the Syrian army recaptured oil fields, including the country's largest, while advancing against Kurdish forces.
On Saturday, Syria's government freed at least 126 minors being held in a prison for ISIS detainees in Raqqa province in northern Syria after taking over the facility from Kurdish forces.