A publisher of secular and atheist books was hacked to death in Bangladesh on Saturday, according to police. In a separate attack hours earlier, two secular writers and a publisher were shot and stabbed at a publishing house in Dhaka.
A local affiliate of al-Qaeda claimed responsibility for the attacks, according to the BBC.
There have been a series of attacks targeting secularists since blogger Avijit Roy was hacked to death in February.
Faisal Abedin Dipon, 43, was found dead in his office at the Jagriti Prokashoni publishing house, senior police officer Shibly Noman said.
"I saw him lying upside down and in a massive pool of blood. They slaughtered his neck. He is dead," his father, the writer Abul Kashem Fazlul Haq said, quoted by AFP.
Dipon had filed complaints to the police after he received death threats on Facebook, friends said according to the Guardian.
Earlier on Saturday, publisher Ahmed Rahim Tutul was attacked and seriously wounded at Shudhdhoswar publishing house. Two writers were also injured in the attack.
The three men were stabbed and then locked in an office as the assailants fled the scene, police said.
All three have been hospitalised, and Tutul was in critical condition, according to police.
Ansar al-Islam, al-Qaeda's Bangladeshi affiliate, posted online claiming responsibility for the attack, according to the SITE Intelligence Group, which monitors jihadist online postings.
They accused the "secular and atheist publishers" of publishing books by blasphemers which dishonoured the Prophet Muhammed, and threatened furher attacks.
Robert Gibson, the British High Commissioner to Bangladesh has condemned Saturday's attacks. "Violence is never the answer or acceptable in any circumstances," he tweeted.
Since the murder of Roy, a critic of radical Islamism and US citizen of Bangladeshi origin in February, which left his wife, fellow blogger Bonya Ashmed seriously injured, Bangladesh has been rocked by a series of attacks claimed by Islamic extremists. Three other bloggers have since been killed.