Prime Minister Sheikh Hasina on Sunday called for calm after at least four people were killed when police fired on thousands of Bangladeshi Muslims protesting Facebook messages that allegedly defamed the Holy Prophet (PBUH).

Mob attacks over online posts perceived to be blasphemous have emerged as a major headache for security forces in Bangladesh, where Muslims make up some 90 percent of the country's 168 million people.

Some 20,000 Muslims demonstrated at a prayer ground in Borhanuddin town on the country's largest island of Bhola to call for the execution of a young Hindu man charged with inciting religious tension through online messages.

Copyright Agence France-Presse, 2019