US Central Command chief Gen. Kenneth McKenzie on Monday (July 22nd) visited northern Syria for the first time since taking up the post, AFP reported.

McKenzie -- who oversees US operations in the Middle East -- succeeded Gen. Joseph Votel in late March.

Votel's departure came just days after the Syrian Democratic Forces (SDF) recaptured the last patch of territory from the "Islamic State of Iraq and Syria" (ISIS) in eastern Syria with US support.

After the months-long campaign, Syria's Kurds now hold thousands of ISIS suspects in jails and tens of thousands of women and children in overcrowded camps for the displaced in parts of north and north-eastern Syria that they control.

They have repeatedly urged foreign nations to repatriate around 1,000 alleged foreign extremist fighters and tens of thousands of non-Syrian women and children linked to the group, but most countries have been reluctant.

During his visit, McKenzie and SDF chief Mazlum Abdi discussed "the problem of camps and ISIS detainees held by the SDF", the alliance said in a statement.

They also spoke of co-ordination between the international coalition and the SDF to carry on hunting down ISIS sleeper cells, it said.

The extremist group has continued to claim deadly car bombings and arson attacks on key wheat fields in SDF-held territory, despite its territorial defeat.