US-based monitoring group SITE reported that ISIS, which has claimed responsibility for many recent attacks in Bangladesh, said it targeted worshippers at the mosque in Bagmara town, some 250 kilometres from Dhaka, according to bdnews24 online.
The monitoring group quoted ISIS as saying that the bomber detonated an explosive belt at a mosque of the "polytheist Qadiani sect," a derogatory term for Ahmadi Muslims, the report said.
SITE had reported ISIS claiming credit for several previous militant attacks.
The Christmas-day attack came as Muslim-majority Bangladesh celebrated the birth anniversaries of Prophets Mohammad and Jesus Christ amid festivity and tight security.
"The explosion killed the suicide bomber and injured 10 others," a police officer has said.
The attacker had exploded the bomb he had concealed under his garments.
In recent months, homegrown militant group Jamayetul Mujahideen Bangladesh (JMB) and ISIS have claimed responsibility for bomb attacks on a shrine and a mosque of minority Shia Muslims in northern Bangladesh.
Members of other minority groups, including Sufis - who adhere to a mystical form of Islam - have also been attacked and killed in recent months, and two Christian priests have survived attacks claimed by Islamist militants.
Bagmara area is the hometown and stronghold of outlawed JMB kingpin Siddiqul Islam Bangla Bhai, who was executed along with three other top leaders of the Islamist group in 2007.
Bangladesh has seen several violent incidents in recent months, including attacks on foreigners and secular bloggers claimed by the IS, although the government says the attacks have been carried out by local Islamist radical groups.
Last week, six people were injured when two Molotov cocktails exploded at a mosque inside a major naval base in Bangladesh's port city of Chittagong after Friday prayers.
The attacks have alarmed the international community and raised concerns that religious extremism is growing in the traditionally moderate South Asian nation.
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