The so-called Islamic State group has said it carried out an attack on a Shia mosque in Bangladesh on Thursday, according to reports.
At least one person was killed and three were injured after gunmen opened fire during evening prayers at a mosque in Bogra in the north-west.
Bangladesh's government says IS is not active in the country and blamed local militant groups.
Two suspects are being held for questioning, police say.
A statement on an IS-affiliated Twitter account claimed the group was behind the attack, saying that "soldiers of the caliphate targeted a place of worship for the apostates", according to SITE monitoring service.
The incident comes a month after a grenade attack on a Shia shrine in Bangladesh's capital Dhaka, which killed one and injured 80.
IS claimed it was behind the attack but the government blamed local militant groups including Jamaat-ul-Mujahideen (JMB).
On Wednesday, police said they had killed Al Bani, who headed the military wing of JMB, and that he died in an exchange of fire as they tried to arrest him.
Bangladesh is a predominantly Sunni Muslim nation, but attacks on Shia Muslims are extremely rare.
However, there has been a rise in attacks on foreigners and secular bloggers in recent months.
Both attacks were claimed by IS but the government blamed the killings on local militants.
Last week, gunmen wounded an Italian priest in north-west Dinajpur district. No group said it carried out the attack.
Extremists have carried out a series of high-profile attacks on secular writers, hacking to death four bloggers - one a US citizen - so far this year.