Some members of the Islamic State group's religious "police” have been kidnapped in eastern Syria, according to reports. The news comes a day after a senior figure in the force was found murdered in the same area.

The Syrian Observatory for Human Rights said that the religious police were ambushed by gunmen in the eastern city of Mayadin. The Observatory said that the self-appointed officials were on patrol when they were kidnapped, and that the number of men abducted was unclear. The force, known in Arabic as al-Hesbah, enforces a strict interpretation of Islamic law in areas controlled by ISIS.

The kidnappings come just days after a senior official in the group was found beheaded in al-Mayadeen city in Syria's Deir el-Zour province. The unnamed man was an Egyptian national who was the deputy “emir” of al-Hesbah in the province.

The man was found decapitated, with the message, “This is evil, you Sheikh,” written on his body, and a cigarette placed in his mouth, according to the Guardian. ISIS has banned smoking in public in many of the areas under its control.

“We do not know whether Islamic State killed him or whether it was local people or other fighters,” said Rami Abdulrahman, director of the U.K.-based Observatory. “Either way it is important, because he was a very important man,” he said, adding that he believed that it was the first time that an al-Hesbah member had been killed in this way, the Telegraph reported

There has been violence against al-Hesbah forces in recent months, with many locals feeling that the group arrests people and insults their dignity for trivial offenses, such as smoking, Agence France-Presse cited Abdulrahman as saying.

ISIS militants and religious police have enforced brutal punishments on citizens in the territories it controls for so-called violations of Islamic law. People have been stoned to death or beheaded for incurring the displeasure of the group, including most recently a street magician in the Syrian town of Raqqa

The group controls large parts of Syria and Iraq, and has declared an Islamic “caliphate” in its territory.