Syrian defence ministry says extension aims to help transfer of ISIL prisoners from facilities previously held by SDF.

A ceasefire agreement between Syria’s military and Kurdish-led forces has been extended for 15 days, the Syrian Ministry of Defence announced.

The ministry said late on Saturday that the extension, which began at 11pm local time (20:00 GMT), aims to support a United States operation to transfer ISIL (ISIS) prisoners from detention facilities previously controlled by the Kurdish-led Syrian Democratic Forces (SDF).

The SDF also confirmed that the ceasefire was extended, stressing in a statement that the deal “contributes to de-escalation, the protection of civilians, and the creation of the necessary conditions for stability”.

Reporting from the Syrian capital Damascus, Al Jazeera’s Ayman Oghanna said the announcement has spurred a feeling of relief in the country.

“While this ceasefire is welcome in Syria, there’s still a lot of concern because the central issue that has caused the fighting between the SDF and the government hasn’t been resolved,” he said.

“And that issue is integration: integrating SDF fighters and civil institutions into [Syrian] government institutions.”

Syrian President Ahmed al-Sharaa signed a deal with the SDF in March of last year to integrate the group into state institutions following the fall of longtime leader Bashar al-Assad.

But the plan faltered amid disagreements between the two sides over how best to implement the agreement, spurring a wave of deadly clashes in several parts of the country in recent weeks.

Earlier this week, Damascus announced a four-day truce to halt a wave of fighting that saw Syrian government forces rapidly advance and seize territory previously held by the SDF.

Syrian ​forces were approaching a last cluster of Kurdish-held cities in the northeast when the ‍ceasefire was announced on Tuesday, giving the SDF until Saturday night to come up with a plan to integrate with Syria’s army.

The advance has brought key oil fields, hydroelectric dams and some facilities holding ISIL fighters and affiliated civilians – including al-Aqtan prison in Raqqa province – under government control.

US President Donald Trump’s administration has been calling on both the Syrian government and the SDF to ensure that the ceasefire holds.

On Wednesday, Washington announced it had begun transferring ISIL-linked detainees from Syria to Iraq. The US military has said as many as 7,000 people could be transferred to Iraqi-controlled facilities.

“We are closely coordinating with regional partners, including the Iraqi government, and we sincerely appreciate their role in ensuring the enduring defeat of ISIS,” US Admiral Brad Cooper, the head of US forces in the Middle East, said.