Assailants with cleavers and machetes on Tuesday killed another blogger in Bangladesh, the third blogger in that country murdered in as many months, the Committee to Protect Journalists said.

Another blogger killed in Bangladesh earlier this year used Facebook as his medium, the committee said.

The committee said that Ananta Bijoy Das, who wrote about science and railed against religious fundamentalism, was killed Tuesday by four masked men in the northeastern city of Sylhet in broad daylight.

"The government of Prime Minister Sheikh Hasina must take urgent steps to ensure the security of critical bloggers in Bangladesh given this series of murders," CPJ Asia Program Research Associate Sumit Galhotra said. "Authorities can show their commitment to curbing this violent trend by finding Ananta Bijoy Das's killers and bringing them to justice."

The death of Das brings to at least 20 the number of writers murdered globally this year, according to CPJ statistics. Bangladesh is ranked 13th globally with at least 16 killed since 1992.

No immediate arrests have been made in connection to Das' death.

Das, meanwhile, was said to be the editor of Jukti, a scientific magazine, and also contributed to the blog Mukto Mona, which was run by Avijit Roy, a Bangladeshi blogger also hacked to death in February.

A similar type of attack killed blogger Washiqur Rahman Babu in March in the Bangladeshi capital of Dhaka. CPJ said that the blogger "wrote about religion, science, and against communalism, mainly on Facebook."

Arrests have been made in connection to these two bloggers' deaths, "but no one has been convicted to date," CPJ said.