Dhaka, Jun 7 (PTI): Three suspected Islamists were killed today in separate gunbattles with Bangladesh police which launched a massive crackdown on extremists as a Hindu priest became the latest casualty in a wave of attacks on secular activists and minorities in the Muslim-majority country.

The three were operatives of the outlawed Jamaatul Mujahideen Bangladesh (JMB) outfit which was targeted by Superintendent of Police Babul Aktar whose wife was brutally killed by the militants on Sunday.

Two operatives of JMB were killed in a shootout with police detectives here while another member of the same outfit was killed in a gunfight with police in the northwestern Rajshahi city, police said.

"The two were killed in a predawn encounter at Kalshai area (in the capital)... they first fired gunshots, prompting our detectives to retaliate as they raided the area on a secret tip-off," Dhaka police's spokesman Masudur Rahman said.

The two are said to be involved in several recent attacks including the bombing of a Shiite mosque and the murder of a liberal professor, police said.

The two militants succumbed to their bullet wounds as doctors declared them brought dead. The third operative was gunned down in a "gunfight", hours after he was arrested from the outskirts of the northwestern Rajshahi city, police said.

"We took Jamal Uddin (third operative) as our escort to a JMB den but his cohorts opened fire sensing our presence at their hideout... Jamal was caught on the line of fire as we retaliated and died instantly," a police officer said.

He claimed that two policemen were also injured in the operations. A small cache of arms and ammunition was seized from the spot.

The developments came as suspected militants hacked to death a Hindu priest in western Jhinaidah district, the second priest to be killed this year, two days after they killed a Christian businessman and the wife of a police officer, who visibly earned the militants' wraths by leading a clampdown against the extremists.

There have been systematic assaults in Bangladesh in recent months specially targeting minorities, secular bloggers, intellectuals and foreigners.

The ISIS and al-Qaeda in Indian Peninsula have claimed responsibility for some of the attacks although the government denies their presence in Bangladesh.