Police said on Sunday they had detained three suspected members of a banned militant group and found a sniper rifle, ammunition, explosives and military suits in a hideout in southeastern Bangladesh.

The raid came days after police busted a militant hideout in the capital Dhaka as security forces stepped up a hunt for Islamist militants behind a spate of recent attacks in the Muslim-majority nation.

Police searched an apartment in the port city of Chittagong based on information from the three members of the banned Jamaat-ul-Mujahideen organization who were caught in an earlier raid, Chittagong city police commissioner Mohammad Abdul Jalil Mondal said.

"A sniper rifle, ammunition, explosives, detonators, army uniforms and bomb-making materials were found in the apartment," he told a news conference.

The group was believed to be behind a series of recent attacks, including bombings of a Shi'ite shrine and the shooting of three foreigners, two of whom have died.

Bangladesh has suffered a wave of Islamist militant violence in recent months, including a series of attacks on mosques, Christian priests and Hindu temples.

Islamic State has claimed responsibility for some of the attacks, including a bomb attack at a mosque of the minority Ahmmadiya Muslim community during prayers on Friday. Police have confirmed the person killed was the bomber himself.

The government has denied that Islamic State has a presence in the country of 160 million people. It blames Islamist political opponents for instigating the violence.