DHAKA: Bangladesh police were Tuesday investigating a new hit-list that includes the head of a university, journalists and ruling party officials, after a series of gruesome killings.

Police said they were taking seriously the threat to kill 10 people listed in a leaflet that was sent to a press club in the northwestern town of Natore on Monday by a hitherto unknown group.

Among those named was the head of Rajshahi University, where a liberal professor was hacked to death by suspected militants less than two weeks ago.

"The leaflet bears the name of Islami Liberation Front. It said it has launched a mission to kill the 10 people," Natore police chief Shymal Kumar Mukherjee told AFP. "We don't know anything about this group. There are no previous information about this group. We have taken the matter seriously," he said.

The Muslim-majority nation is reeling from a string of killings of secular and liberal activists and religious minorities by suspected militants.

Police in the city of Rajshahi said they were guarding those named and investigating the authenticity of the threat.

"We're giving special attention to these people," deputy chief of Rajshahi police Sardar Tamizuddin Ahmed told AFP.

'Bring killers to book'

Police said more than 1,000 students and teachers and students rallied on the Rajshahi University campus on Tuesday to protest at the murder of English professor Rezaul Karim Siddique, who was a poet and leading cultural activist.

Shortly after his killing, which has been claimed by the militant Islamic State(IS) group, two gay activists were hacked to death elsewhere. Their killings were subsequently claimed by a Bangladeshi branch of Al Qaeda.

Teachers and students have been boycotting classes at the university since Siddique's murder on April 23, demanding justice and the arrest of the killers.

"The killers must be brought to book immediately. The government must protect the teachers and liberal voices as we're all feeling insecure," the head of Rajshahi University Teachers Association, Shahid Ullah, told AFP.

Bangladesh's government has been criticised for not doing enough to stem the tide of violence.

At least 30 members of religious minorities, secular bloggers and other liberal activists, foreigners and intellectuals have been murdered in the past three years.

The government denies outside involvement in the killings, saying neither IS nor Al Qaeda have a presence in the country, instead blaming banned local militant groups for the attacks.

National police chief A.K.M Shahidul Hoque Tuesday denied authorities were not doing enough to bring the perpetrators to justice.

He said there had been 37 attacks related to militancy since February 2013, when an atheist blogger was hacked to death.

"We were able to unearth the motives in 33 cases and have detained 144 people in connection with the cases," he told reporters.