Dhaka: In an hour crackdown of Rapid Action Battalion (RAB), Special Weapons And Tactics (SWAT), and police in a suspected militant den on Dhaka’s Kalyanpur area at least nine suspected militants were killed in the early hours of Tuesday.

‘Nine Islamist militants were killed after two hour-long gunfight’ deputy commissioner of Dhaka Metropolitan Police (DMP) Masud Ahmed told AFP, adding another extremist was shot and arrested during the raid in Kalyanpur neighbourhood.

The operation called ‘Operation Storm 26’, started at about 5:30am and was conducting for an hour.

However, Inspector General of Police (IGP) AKM Shahidul Haque claimed they belonged to a a Bangladeshi group blamed for Gulshan café attack earlier this month in which 20 hostages were killed and had been planning another large-scale assault.

A.K.M Shohidul Haque told reporters they suspected all 10 were members of the homegrown extremist group Jamayetul Mujahideen Bangladesh (JMB), which was blamed for the Gulshan cafe attack.

But a police official said the wounded survivor who was rushed to Dhaka Medical College Hospital after Tuesday's raid claimed that all of those inside the hideout were IS followers.

‘His name is Hasan. He said they are IS members,’ the police official told AFP on condition of anonymity, adding the 25-year-old was a cook and hailed from the northern district of Bogra, home to two of the five cafe attackers.

He also stressed that the nine killed in Operation Storm 26 had no connection with Islamic State jihadists even though they were wearing the group's signature black robes.

‘We think they are all JMB members... We have not found any link with IS. They are all local Bangladeshi militants,’ he said.

Dhaka Metropolitan Police (DMP) Deputy Commissioner Masud Ahmed told BBC Bangla the law enforcers are conducting search in the militant hideout. They recovered some ammunition from the building.

Police said they cordoned off an apartment building in Kalyanpur after suspects threw a small hand bomb at officers who were conducting a ‘block raid’ in the area after midnight.

The gunmen exchanged fire intermittently throughout the night and shouted ‘Allahu Akbar’ as the neighbourhood was sealed off by hundreds of heavily armed police and RAB, police said.

‘This morning police launched operation Storm 26 and was able to destroy the militants. We’re now sweeping the place,’ Dhaka additional police commissioner Sheikh Maruf Hasan who led the raid told AFP.

 ‘Their dress and their slogans before and after the attack all proved that they are members of (Islamist) militant force,’ Hasan said, adding that they were wearing black tunics and shouting ‘Allahu Akbar’.

Bangladesh is reeling from a wave of deadly attacks by Islamist extremists.

Earlier this month five armed men stormed an upscale cafe in Dhaka’s diplomatic zone and killed at least 20 hostages including 18 foreigners, in an attack claimed by the Islamic State group.