A suspected Islamic militant and three others have been killed in a bomb blast after security forces besieged a house in eastern Bangladesh, officials say.
Mollah Omar, a member of the banned Jamaat-ul-Mujahideen, died in the blast in the town of Comilla, along with his wife and two children, officials said.
The deaths follow the recent arrests of the group's chief, Abdur Rahman and his deputy Siddiqul Islam or Bangla Bhai.
The government blames the militant group for a recent spate of bombings.
Mr Rahman's son, Nabil, was one of two people arrested at the site of the explosion in Comilla, Rapid Action Battalion (RAB) officials said. He was wounded.
Reports say some 300 RAB personnel surrounded the house which was being used by Mollah Omar and his family in Comilla, about 88km (55 miles) east of the capital, Dhaka.
A son of JMB leader Rahman, Nabil, was arrested in the siege
Security officials say they heard two powerful explosions after they laid siege to the two-storey house.
Mollah Omar ignored calls for his surrender and exploded several bombs during the three-hour siege, RAB officials said.
On entering the house the officials say they found his body and those of his wife and two children in a pool of blood.
The authorities say it is still not clear whether Mollah Omar exploded the bombs to commit suicide or in an attempt to escape.
Abdur Rahman and Bangla Bhai were arrested within days of each other earlier this month.
In February, a court sentenced the two men - and two others also accused of Islamic militancy - to 40 years in prison in absentia for a bomb attack that killed two judges last year.
There have been a spate of bombings in recent months in Bangladesh.
Last August, about 500 small bombs were set off in all but one of Bangladesh's 64 districts in the space of an hour. Three people were killed and about 100 injured.
A number of subsequent bomb attacks have targeted judges and court rooms.
More than 100 cases have been filed against alleged members of the JMB in connection with the bombing campaign.
The Jamaat-ul-Mujahideen has been demanding the introduction of Sharia law in Bangladesh.