Dhaka: The self-styled Islamic State (IS) group has claimed responsibility for the murder this week of a Bangladesh policeman, as fears of Islamist violence grow in the moderate Muslim-majority country.

A group of unknown men stabbed a police officer to death on Wednesday just outside the capital Dhaka, while another was badly injured, the second such attack in less than a month.

Home Minister Asaduzzaman Khan blamed local hardline Islamists, whom the government also suspects are behind a series of murders this year of secular bloggers and a publisher of secular books.

But the IS said its "soldiers of the state in Bangladesh" carried out Wednesday's killing, according to the US-based jihadist monitor group SITE.

In recent weeks, IS has also claimed responsibility for murders of an Italian aid worker and a Japanese farmer, along with a blast at the country's main Shiite shrine which left two people dead.

If the latest claims are true, it would be the first time IS has targeted an arm of the Bangladesh government. The government has rejected the jihadist group's previous claims, saying it does not have any presence in the country.

An Al Qaeda branch has also claimed responsibility for the blogger and publisher attacks, calling the victims "atheists and blasphemers".

The government has instead blamed local Islamists, along with the main opposition party and its Islamist ally, for orchestrating the violence to destabilise the country.

Prime Minister Sheikh Hasina's government launched a crackdown on local Islamist groups after facing Western criticism this year of failing to stop the bloodshed.