An Islamist group called called Ansar Bangla 7 has claimed responsibility on Twitter for the murder of writer Avijit Roy who authored the Mukto Mona blog.

The account belonging to the group said Roy was "top target 4" for fanatics because of his online writing, which some Muslims branded blasphemous.

Graphic photos taken at the scene where Roy was attacked with machetes in Dkhara university, were published with slogans celebrating his death.

Messages included "Allahu Akbar..A great success today here in Bangladesh." One explained: "The guy [...] was targeted because of his crime against Islam."

It is not certain that the Twitter account "Ansar Bangla 7" is officially linked with Roy's killers and the claim of responsibility cannot be verified.

Roy, who was a high-profile secular blogger, is repeatedly referred to as a "target" in several posts. It was also claimed he had been a target for four years before he was killed.

Also published on the website are posters with inflammatory slogans such as, "A bullet a day keeps the infidel away."