Security forces arrested the suspected military commander and the alleged accountant of a banned Islamic group blamed for a wave of deadly bombings in Bangladesh, claiming a breakthrough Wednesday in their fight against the militants.

Investigators interrogated the men in hopes they could help crack Jumatul Mujahideen Bangladesh, which officials say carried out attacks that have killed 22 people and wounded scores since November.

"We hope to get some very important information from them," said Masuq Hassan Ahmed, a spokesman for the elite Rapid Action Battalion, which includes police and soldiers.

Jumatul Mujahideen Bangladesh wants to establish strict Islamic rule in the country of about 140 million people, which was set up as a secular state when it won independence in 1971 from Pakistan, where Islam is the official religion.

Elite forces caught Ataur Rahman, the group's reputed military commander, in a raid late Tuesday at Dhaka's Tejgaon Polytechnic College, where he apparently had gone to meet someone, Ahmed told reporters.

Rahman, also known as Sunny, denied involvement in the bombings, but has admitted to being a member of Jumatul Mujahideen and the younger brother of the group's fugitive leader, Shaikh Abdur Rahman.

Agents also nabbed Fariduzzaman Swapan, who is believed to be an accountant for Jumatul Mujahideen, in a separate raid Tuesday in Dhaka, Ahmed said.

Swapan was being investigated for suspected money laundering because he maintains several bank accounts in his own name, although he denies any ties to the militants, Ahmed said.

Neither of the men, both of whom are in their late 30s, have been charged.

On Wednesday, police uncovered two weapons caches believed to belong to the militants, although officials would not say if the raids resulted from information provided by the suspects.

Police found dozens of grenades and revolvers along with explosives, detonators and other bomb-making materials in a house in Dhaka, Ahmed said.

Police in the southeastern port of Chittagong also raided a shanty, arresting two suspected militants and seizing detonators, explosives, fake passports and items that could be used to disguise bombs, like books with pages cut out, police officer Mohammad Osman Gani said.

Police also said they recovered hundreds of books, leaflets and cassettes about jihad, or holy war, during both raids.

Critics say the government, ruled by a coalition that includes two Islamic parties, initially was hesitant to go after the group when the militants emerged last year in northern Bangladesh.

But after a Dec. 8 suicide blast that killed eight people, including the bomber, in a town north of Dhaka, officials vowed tough action against the group, which claims to have 10,000 members.

Officials say they are investigating Bangladeshi media reports that members of the group fought with mujahedeen against the Soviet occupiers of Afghanistan in the 1980s.

So far, the militants have largely targeted government offices and the courts, although a cultural group that had recently staged anti-militant concerts appeared to be the target of last week's suicide bombing.