Syria's Kurds have agreed to allow thousands of Syrians including relatives of extremists to leave a squalid and over-populated camp they administer, a top official said Monday.

"Syrian nationals will leave Al Hol camp and only foreigners will remain," said Riyad Derar, the co-chair of the Syrian Democratic Council, the political wing of the region's main military force.

"In Al-Hol, there are Syrian relatives of the Daesh extremist group fighters and they too will be released" with guarantees from their families, Derar told AFP.

Syrian extremists who are currently being held by Kurdish authorities in prisons in northeast Syria will not be included in the blanket release, the SDC official added, without providing a timeline.

The overcrowded Al-Hol camp is home to 64,377 people, including 24,300 Syrians who were either captured or displaced by fighting, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA).

Iraqis make up the bulk of foreigners in Al-Hol which is also home to Western nationals many of them relatives of Daesh fighters.

Derar said Iraqis will be allowed to leave on a voluntary basis but he said that many wanted to remain in the camp over fears they would be imprisoned or tried in Iraq for alleged links to Daesh.

The Kurdish authorities' dwindling resources have complicated attempts to properly administer the camp's massive population, which aid groups say suffers from dire living conditions as well as medical and water shortages amid a coronavirus outbreak in the settlement.

Security has also been an issue in the camp which hosts Daesh sympathisers still loyal to the extremist group even though it lost the last scrap of its proto-state across swathes of Syria and Iraq in eastern Syria last year.

"The Al Hol camp is a big burden on the Kurdish administration," Derar said.

Kurdish authorities had already released Syrian residents of Al-Hol in recent months following guarantees from Arab tribes.

According to a July OCHA report, 4,345 Syrians have been released since June last year.