At least four people were killed and about 100 injured when security officials in Bangladesh opened fire during a protest over a Facebook post criticizing Islam’s Prophet Muhammad.

The violence unfolded in the Borhanuddin section of the southern district of Bhola — about 72 miles south of the capital, Dhaka — on Sunday when enraged protesters demanded that a Hindu man be punished for the alleged Facebook comment, local police chief Sarkar Mohammad Kaisar said.

The man, who has not been identified, denied making the comment and claimed that his account had been hacked.

Authorities held a meeting to try to calm the masses as the Facebook post gained attention in the region, but tempers flared even higher and angry protesters began to attack security officials, prompting them to fire their weapons.

Four people were killed and the injured civilians, as well as about a dozen police officials, were being treated at local hospitals, authorities said.

Three people have been detained for allegedly hacking the Hindu man’s account and posting derogatory comments about Muhammad.

Minority groups in Muslim-majority Bangladesh say they often face discrimination. Muslims make up some 90 percent of the country’s 168 million people.

Authorities in the South Asian country, a parliamentary democracy with a legal system based on British common law, have refused to introduce tougher Islamic laws, despite demands by hard-line groups.

With Post wires