BEIRUT (AFP) - The Islamic State in Iraq and Syria (ISIS) group has claimed the arrests of four extremists it classified as "extremists" accused of plotting against the organisation in areas of Iraq and Syria under its control.

In a video purportedly posted by ISIS on extremist websites, a male voice claims to have "captured an extremist religious cell planning to take up arms against the Caliphate," referring to the regions it controls in both countries.

In what ISIS said were confessions, the four detained men said they had plotted against ISIS as the group doesn't view "all Iraqis and Syrians as infidels".

The men, speaking Azerbaijani Turkish, accused ISIS leader Abu Bakr al-Baghdadi of being "an infidel as he takes money from infidels".

The video does not specify when or where the men were arrested but it carries the initials of Syria's Raqa province, a stronghold of ISIS in the north of the war-ravaged country.

The fate of the four detainees is also not revealed, although the video ends with the recitation of a Quranic verse stating that those who fight against God and the Prophet Mohammed deserve to die or have their arms and legs amputated.

The Financial Times newspaper over the weekend reported that 100 foreign ISIS members had been executed by the group after trying to flee Raqa.