A Twitter account, purportedly handled by the militant group Ansar Al Islam, made the claim hours after the attacks on Saturday night.
“We, al-Qaeda in the Indian Sub-Continent, claim responsibility for this operation,” a message posted on the account read.
Machete-wielding assailants barged into the Suddhaswar publisher’s Lalmatia office and hacked Ahmedur Rashid Chowdhury Tutul and two other writers.
Another publisher, Faisal Arefin Dipan of 'Jagriti Prokashony', was found hacked to death at Shahbagh hours later.
Both publishers published works of slain writer-blogger Avijit Roy, who was killed in a similar attack in February. Since then, three other secular bloggers have been killed.
The tweet described the publishers as “apostates”, who frequently published books that “violated the honour of Prophet Muhammad”.
It said the attacks were “vengeance in honour of the messenger of Allah and the religion of Islam”.
Police’s Deputy Commissioner Muntasirul Islam told bdnews24.com that they were investigating the claim.
“Our teams are working to ascertain credibility of the claim,” he said. “We are investigating who tweeted and from where.”
Name of the militant group was previously used to claim credits for the killing of Roy and another secular writer Niladri Chatterjee Niloy in August.