Fighters from the militant Islamic State (IS) group attempted to break out of a detention facility in northeastern Syria but US-backed Syrian fighters “successfully” restored calm, activists and the US-led coalition said on Saturday.

Few details emerged about what transpired a day earlier in the detention facility in the town of Derik, in the Kurdish-administered northeastern Syria.

Activists from the Rojava Information Centre said local anti-terror forces were deployed on Friday around the building and on its roof after the attempted prison break. The activist-run media platform said warplanes flew over the facility.

Col Scott Rawlinson, coalition spokesman, said all detainees were accounted for after the Syrian Democratic Forces “peacefully” dealt with the incident. He said coalition forces supported the SDF with aerial observation but provided no further details.

SDF officials had no immediate comments.

The Kurdish-led SDF is holding hundreds of foreign IS militants in facilities around areas they control in northeast Syria. Many more local suspects are detained separately.

It was not clear if the attempted break-out was among foreign or local detainees. Families of the detainees are held in crammed displaced people's camps in northern Syria, where living and security conditions have been precarious.

Officials from the Kurdish-administered areas have said keeping the hundreds of foreign militants and their families is a “burden” that they can't handle on their own. The officials and the coalition have asked home countries to repatriate their nationals an issue that has triggered a debate in many European countries who cite security concerns.

“The SDF understand well the threat posed by Daesh and are performing commendably in maintaining the security of the detainees in their custody,” Rawlinson said, referring to IS by its Arabic acronym.

After years of battling the militants, the SDF declared military victory against IS last month after recapturing the last speck of land they controlled in Syria, near the border with Iraq.