BEIRUT — Syria's Kurds said on Thursday that Turkish bombardment had hit a prison they use to house captured Daesh (the so-called IS) fighters, despite Ankara's pledge to do nothing to undermine the campaign against the militants.

"The Turkish regime... targeted a section of the Jerkin prison," in the Kurdish-majority city of Qamishli in the northeast, the region's autonomous Kurdish administration said.

"The prison houses some of the most dangerous criminals from more than 60 countries, who committed all kinds of crimes when they were members of the Daesh group," it added.

The Kurdish authorities have repeatedly talked up the threat they say Ankara's offensive poses to the US-led campaign against the militants.

One of the beleaguered Kurds' last hopes is that the prospect of Daesh prisoners breaking out and regrouping with increasingly active sleeper cells will spur the world into action.

But the Kurdish administration made no mention of any breakout from Jerkin prison and the Britain-based Syrian Observatory for Human Rights said Turkish "artillery fire" hit the "vicinity" of the prison, and not the facility itself.

The Kurdish-led Syrian Democratic Forces (SDF), who were the principal ground partner in the US-led campaign against Daesh now hold thousands of captured fighters in jails across the northeast.

Thousands of their relatives are also being held in Kurdish-run camps, where they have stabbed security forces, assaulted aid workers, and attempted to escape. — AFP