Four militants from the Neo Jamaat-ul-Mujahideen Bangladesh (JMB) militant group, who pledged allegiance to the Isis, were killed on Thursday (16 March) when their suicide vests exploded during a raid, according to a senior police official in Bangladesh. One of those killed is a woman.

The operation 'Assault 16' was carried out by Counter Terrorism and Transnational Crime Unit, Special weapon and Tactic Team (Swat), Rapid Action Battalion (Rab) and the district police in Chittagong, around 200km southeast of capital Dhaka.

The raid reportedly started on Wednesday night and 20 members of seven families who were trapped in the building were evacuated before the final attack began on Thursday.

Two policemen were injured when the extremists attacked the police with grenades.

"The operation is over. Our intelligence and bomb disposal and forensic units are now working." police official Mohammad Moniruzzaman told Reuters.

Shafiqul Islam, a senior police officer in Chittagong, said that the militants were shouting "Allahu Akbar" when they started attacking the policemen.

"They were wearing suicide vests which exploded. We are not sure whether they detonated the vests themselves, or they exploded after being hit by bullets. The woman was shot by us."

"We suspect the militants might have had plans to attack foreigners in the city," he added.

Since the cafe attack in July 2016, police say they have killed over 50 militants including the Bangladesh-born Canadian national Tamim Ahmed Chowdhury, a man the police say is its chief planner.

In the last few years, Bangladesh has been rocked by a series of killings of liberals and individuals belonging to religious minorities.

Dhaka attack
Several people died in an attack on the Holy Artisan café in Dhaka, Bangladesh on 1 July 2016Mahmud Hossain Opu/Getty Images