Gunmen have shot and killed a prominent Rohingya leader in a refugee camp in southern Bangladesh, following months of worsening violence in the world’s largest refugee settlement.

Mohib Ullah, chairman of the Arakan Rohingya Society for Peace and Human Rights (ARPSH), was talking with other refugee leaders outside his office after attending evening prayers on Wednesday when at least four assailants shot him dead, said Rafiqul Islam, police spokesperson of Cox’s Bazar.

“Four to five unidentified assailants shot him from close range. He was declared dead at a MSF hospital in the camp,” he told AFP.

Islam said police and the Armed Police Battalion, which is tasked with ensuring security for the country’s 34 Rohingya camps, have stepped up security, deploying hundreds more armed officers.

Mohammad Nowkhim, an ARPSH spokesperson, said Ullah was talking to other Rohingya leaders outside the ARPSH office at Kutupalong, the world’s largest refugee settlement, when he was attacked.

“He was in a pool of blood. He was brought dead to the nearby MSF hospital,” Nowkhim said from an undisclosed location, as he – like many other Rohingya leaders – have gone into hiding after Ullah’s death.

No one has claimed responsibility, but a Rohingya leader told AFP that Ullah was killed by the extremist group Arakan Rohingya Salvation Army, which was behind several attacks on Myanmar security posts in recent years

“It is a work of ARSA,” he said.

Saad Hammadi, Amnesty International’s South Asia Campaigner, said the murder would send a “chilling effect across the entire community.”

“Mohib Ullah was a leading representative of the Rohingya community, who spoke out against violence in the camps and in support of the human rights and protection of refugees,” he said.

“The onus is now on the Bangladeshi authorities to expedite an investigation into his murder and bring all those suspected of criminal responsibility to justice in fair trials.

He added: “Violence in the refugee camps in Cox’s Bazaar has been a growing problem. Armed groups operating drug cartels have killed people and held hostages. The authorities must take immediate action to prevent further bloodshed.”

Ullah, who was 48, emerged as the main civilian leader of the persecuted Muslim minority community when more than 740,000 Rohingya took refuge in camps in Cox’s Bazar, after a military crackdown by the Myanmar army on their villages in Rakhine province in August 2017.

Ullah formed the ARPSH in a Bangladeshi camp months after the influx, and it helped investigate the carnage carried out by the Myanmar armies and Buddhist militias during the crackdown.

In August 2019, he organised a massive rally at Kutapalong camp, the main Rohingya settlement, which about 200,000 Rohingya attended.

That year, he was also flown to the US, where he attended a religious freedom meeting hosted by the US state department and led by then-US president Donald Trump.

But his high profile made him a target of hardliners and he received death threats in 2019. “If I die, I’m fine. I will give my life,” he said at the time.

The sprawling camps in Bangladesh have become increasingly violent, residents say, with armed men vying for power, kidnapping critics, and warning women against breaking conservative Islamic norms.

“We do not expect another progressive leader like him in the Bangladesh camps. We are very saddened by his untimely death,” Rohingya artist Mayyu Khan wrote on Facebook.

The UN refugee agency, UNHCR, said it was “deeply saddened by the killing of Mr Mohib Ullah, a prominent Rohingya refugee representative”.

“We are in continuous contact with law enforcement authorities in charge of maintaining peace and security in the camps,” the UNHCR spokesperson in Bangladesh, Regina De La Portilla, told AFP.