BEIRUT, Lebanon — An Islamic State militant executed his own mother in front of a post office in the northern Syrian city of Raqqa this week, Syrian activists said on Friday, with one monitoring organization adding that the problems began when she tried to persuade him to leave the extremist group.

The fighter, Ali Saqr, 21, killed his mother in front of several hundred people for what the Islamic State called apostasy, according to the Syrian Observatory for Human Rights and Raqqa Is Being Slaughtered Silently, two groups that monitor the conflict through contacts on the ground.

The act was the latest in a chain of brutal and bizarre killings that the Islamic State uses, and often widely publicizes, in efforts to tamp down dissent and to attract recruits.

It would not be the first time that a member of the Islamic State has killed a parent on the group’s orders. Last year, a Lebanese father traveled to Raqqa to try to bring back his son, an Islamic State fighter, and three other children whom the son had persuaded to go there. The son reported the father, who was detained and killed, according to interviews with family members.

Read the article “ISIS Militant Kills Mother on Group’s Orders, Activists Say” on nytimes.com.