Bangladesh’s foreign minister A.K. Abdul Momen vowed on Saturday “stern action” against the killers of Rohingya refugee leader Mohib Ullah.

Mohib Ullah, who was in his late 40s, was killed by unknown gunmen in a camp in Cox’s Bazar on Wednesday night. There have been calls to investigate his shooting.

He led one of the largest community groups to emerge since more than 730,000 Rohingya Muslims fled Myanmar after a military crackdown in August 2017.

“The government will take stern action against those who were involved in the killing. No one will be spared,” the foreign minister vowed.

The minister said in a statement that “vested” interests were responsible for the killing as Mr Ullah had wanted to return to Myanmar.

“The killers of Mohib Ullah must be brought to justice,” Mr Momen stated.

Authorities arrested three refugees in connection with the killing, said Naimul Huq, a police official in Cox’s Bazar, giving no further details.

Mr Ullah was known as a moderate who advocated for the Rohingya to return to Myanmar with rights denied them during decades of persecution.

He was the leader of the Arakan Rohingya Society for Peace and Human Rights (ARSA).

The society was founded in 2017 to document atrocities against Rohingya in their native Myanmar and give them a voice in international talks about their future.

But his high profile made him a target of hardliners, and he received death threats, he told Reuters in 2019.

“If I die, I’m fine. I will give my life,” Mr Ullah had said at the time.

The killing has ignited grief and anger in the camps, the world’s largest refugee settlement, where some residents say the killing is the latest evidence of mounting violence as armed gangs and extremists vie for power.

In a video circulated on social media, his brother, Habib Ullah, who said he witnessed the shooting, blamed the Arakan Rohingya Salvation Army, an armed group active in the camps.

“They killed him as he is the leader and all Rohingya abide by him. Before opening fire, they said he cannot be a leader of Rohingya, and there cannot be any leaders for Rohingya,” Mr Ullah said.

In a post on Twitter on Friday, ARSA said it was “shocked and saddened” by the killing and decried “finger-pointing with baseless and hearsay accusations.”

More than a million Rohingya live in camps, the vast majority having fled neighbouring Myanmar during a military crackdown in 2007 which the United Nations said was with genocidal intent.

Myanmar denies committing genocide, saying it was waging a legitimate campaign against insurgents who attacked police posts.