Gunmen killed seven people and wounded at least 20 Friday in a Rohingya refugee camp in Bangladesh, police and a medic said, an attack that heightens tensions after the recent shooting of a prominent community leader.

The attackers shot and stabbed people attending an Islamic school in the camp, a regional police chief said.

Four people died instantly. Three others died at a hospital in one of the camps in the Balukhali refugee complex, part of a bigger network of squalid settlements housing 900,000 people.

Police did not say how many were wounded but a medic with Doctors Without Borders (MSF) who requested anonymity said about 20 people were badly hurt.

"About 20 seriously injured people came to our hospital, many with no arms, no legs or no eyes. Their condition is very bad," the doctor said.

Police official Kamran Hossain said "Rohingya miscreants" entered the Darul Ulum Nadwatul Ulama al Islamia madrassa before dawn and "randomly hacked and shot people inside".

Security forces immediately sealed off the camp, which houses more than 27,000 people.

Camp residents shared images on social media of bodies on the floor of the madrassa. The images could not be independently verified.

"We arrested one attacker immediately after the incident," local police chief Shihab Kaisar Khan told reporters.

The man was found with a gun, six rounds of ammunition and a knife, he added.

Many Rohingya activists have gone into hiding or sought protection from the police and UN agencies since the killing of community representative Mohib Ullah in the nearby Balukhali camp on September 29.

The 48-year-old teacher had become a leading voice for the stateless community. He met then US president Donald Trump at the White House in 2019.

Some activists blamed the killing on the Arakan Rohingya Salvation Army (ARSA), though the armed group denied involvement.

ARSA is the militant group accused of being behind attacks on Myanmar security forces in 2017 that set off a military clampdown and a mass exodus into Bangladesh by 740,000 Rohingya.

It is also involved in drug smuggling and other illegal activities and is trying to increase its control in the Bangladesh camps.

The refugee camp complex houses more than 900,000 people from Myanmar
The refugee camp complex houses more than 900,000 people from Myanmar AFP / MUNIR UZ ZAMAN

A prominent Rohingya expatriate who knew the madrassa teachers blamed ARSA for the shooting, saying the school had refused to pay the group.

"Since last year ARSA has ordered all madrassas to pay them 10,000 taka ($120) a month and every teacher 500 taka a month. But the madrassa which was attacked today refused," he said, speaking on condition of anonymity as he fears his relatives in the camps could be targeted.

"ARSA carried out the killings to establish their full control in the camps. After Mohib Ullah's killing, this carnage was a kind of stern message sent by the militant group."

A rights worker confirmed "the seminary never recognised ARSA's control in the camps,"

There was no comment on Friday from ARSA.

Other activists said the camp's narrow streets are taken over by militants and criminals after dark when police barely patrol.

"They (police) seem intimidated and reluctant. A serious tension lingers within the camps since Ullah's murder," Kyaw Min, a leader of Ullah's Arakan Rohingya Society for Peace and Human Rights (ARSPH), told AFP in a recent interview.

Bangladesh police have insisted that full security is provided.

Activists say there is fear of more violence in the camps.

"Security was tightened after Ullah's death. But in less than a month seven people have been killed. How can we trust the increased security?" said Hakim, a refugee who asked to use only one name.

Human Rights Watch said in a statement this month that at least a dozen activists have approached the UN refugee agency, the UNHCR, since the killing of Ullah.

Family members and other civil society leaders who had been threatened by militants have already been shifted to safe locations by the authorities, they told AFP.

UN High Commissioner for Human Rights Michelle Bachelet called Ullah's death "a clear example of the insecurity in the camp and the apparent attempts to silence moderate civil society voices".