Around 20,000 Muslims demonstrated demanding for the execution of a Hindu man charged for inciting religious tensions.

Bangladesh Prime Minister Sheikh Hasina called Sunday for calm after four people were killed by security forces, and more than 50 others injured during protests against Facebook messages allegedly denigrating Muhammad, the Prophet of Islam.

"At least four people were killed and up to 50 people were injured," police inspector Salahuddin Mia told AFP, while the death toll is expected to rise according to local doctor Tayebur Rahman who informed that seven among the 43 people transferred to the hospital are fighting to stay alive.

Police stated they had to open fire in self-defense against the mob because some demonstrators were throwing rocks at them.

In the country where Muslims constitute nearly 90 percent of the population, around 20,000 Muslim people demonstrated in the south-central town of Burhanuddin located in Bhola Island, the largest island of Bangladesh. The protesters were demanding the execution of a young Hindu man charged for provoking religious tensions via messages online.

However, Hasina said the suspect’s Facebook account had been hacked by a Muslim person to spread lies.

"We saw rumors are being spread in Facebook to create an environment of anarchy. Who are they? What is their intention?" the premier said in a speech to her political party's members.

Bhola's deputy police chief Sheikh Sabbir told AFP that the man came Saturday to the police station, claiming his Facebook account was hacked.

"We also suspect that his account was hacked and these contents were spread through Facebook messenger," he said. However, the charges have not been dropped.

The constitution of the South Asian country designates Islam as the state religion but upholds the principle of secularism. Yet, Bangladesh’s religious minorities still face regular threats and have been hit by a series of violent incidents since 2012.