DHAKA (Reuters) - Three assailants sped up to a Bangladeshi tailor’s shop by motorcycle on Saturday, dragged out the Hindu owner and hacked him to death, police said, in an attack claimed by Islamic State.

Police official Abdul Jalil, quoting witnesses, said the attackers fled the scene after killing 50-year-old Nikhil Chandra Joardar outside his shop in the town of Tangail, 80 km (50 miles) northwest of the capital Dhaka.

Islamic State militants claimed responsibility for the killing, saying the tailor had blasphemed Prophet Mohammad, the U.S.-based monitoring service SITE said.

The attack came days after a Bangladeshi gay rights campaigner and his friend were killed in a similar manner in a Dhaka apartment.

Islamist militants have targeted atheist bloggers, academics, religious minorities and foreign aid workers in a series of killings that dates back to February 2015 and has claimed at least 20 lives.

International human rights groups say a climate of intolerance in Bangladeshi politics has both motivated and provided cover for perpetrators of crimes of religious hatred.

Police said they were investigating whether Joardar’s killing was connected to a complaint made against him for making a derogatory comment about Prophet Mohammad.

He was in jail for a few weeks in 2012 but released after the complaint against him was withdrawn, said Jalil.

The Islamic State and a group affiliated to al Qaeda have issued similar claims of responsibility in the past, but the authenticity of Saturday’s statement could not be immediately verified.

Three people, including a local Islamist party leader, have been picked up for questioning, police said on Sunday.

The Bangladeshi government has denied that Islamic State or al Qaeda have a presence in the country of 160 million people. Police say home-grown militants groups are behind the attacks.

Western security experts doubt that there are any direct operational links between Islamic State, based in the Middle East, and militants operating on the ground in Bangladesh.

But they do say that claims and statements of support for militant attacks through their propaganda channels allows them to create the impression of being in league together.

Human rights activists have urged mainstream politicians in Bangladesh to abandon sectarian hostilities that date back to the 1971 war of independence, and to engage in a constructive dialogue that would deprive Islamist extremists of cover for their attacks.