Unesco has condemned the murder of blogger Ananta Bijoy Das and has called upon authorities to punish the culprits involved.

In a condemnation message issued from Paris yesterday, Irina Bokova, the director-general of Unesco, also called upon Bangladesh authorities to ensure trial of the killers.

"I condemn the murder of Ananta Bijoy Das and call on the authorities to ensure that those responsible for this killing are brought to justice," the Unesco chief said.

"Punishing such attacks is indispensable to maintain free public debate and free expression by media professionals and committed citizens alike," she added.

Ananta Bijoy Das, 33, was killed by masked assailants in broad daylight in Sylhet city. He was a blogger, a progressive activist and local organizer of Gonojagoron Mancha.