An Indonesian court has sentenced a group of Muslim extremists involved in a deadly mob attack on members of the Ahmadiyah Muslim minority sect to several months in jail. Human rights groups are criticizing Thursday’s ruling for falling far short of the maximum penalty and say it will encourage more violence against religious minorities.

The court convicted 12 people for involvement in a February attack on about 20 members of an Ahmadiyah sect in western Java. Those convicted received sentences between three to six months in jail.