BEIRUT: In a shocking low even by the standards of Daesh, a terrorist has publicly executed his own mother after accusing her of apostasy.

Ali Saqr Al-Qasem, 20, shot his mother Lena, 45, in the head with an assault rifle in front of a large crowd.

The activist group Raqqa is Being Slaughtered Silently said Lena is understood to have been accused of apostasy — a crime that usually means leaving one’s religion but in practice is used by Daesh as a justification for murdering anybody who doesn’t support or speaks out against the terror group.

The woman had warned her son that a US-backed alliance would wipe out Daesh and had encouraged him to leave the city with her.

She was detained after Al-Qasem informed the group about her comments, according to the British-based Observatory, which monitors the war through a network of sources on the ground.

It is not known why her son was given the task of killing his own mother but the reason the execution took place outside Raqqa’s post office is because that is where Lena had worked.

The news came as Daesh chief spokesman in neighboring Iraq, Abu Mohammed Al-Adnani, was reportedly left with severe injuries following an airstrike.

Al-Adnani, who has been singled out as a potential successor should anything happen to the terrorist leader Abu Bakr Al-Baghdadi, required initial emergency treatment in the occupied city of Hit after losing large amounts of blood, Iraq’s Joint Operations Command said.

Al-Adnani has been the chief propagandist for the hard-line group since he declared in a June 2014 statement that it was establishing a modern-day caliphate.

William McCants, a Brookings scholar who is author of the book “The ISIS Apocalypse,” said if true, Al-Adnani’s wounding could be a significant setback for Daesh.