Ten suspects were interrogated Tuesday, a day after several bombs exploded at court buildings in three Bangladesh (search) towns, killing two people and wounding at least 25, authorities said.

Some of the suspects were carrying handwritten leaflets from the banned Islamic group Jumatul Mujahideen Bangladesh (search) calling for establishing strict Islamic rule in this impoverished Muslim-majority nation, a statement from the police headquarters said.

The same group is suspected to be involved in countrywide explosions of more than 430 small homemade bombs on Aug. 17 that left two people dead and about 125 injured.

Army experts gathered splinters of the bombs that went off in crowded court buildings in Chittagong, Chandpur and Laxmipur towns in southeastern Bangladesh on Monday. The experts will try to determine the types of the explosive devices, authorities said.

"We shall not spare those responsible for the attacks," Junior Home Minister Lutfozzaman Babar (search) told reporters Tuesday. "Vigorous investigation is going on."

After Monday's attacks, security was tightened at courts, rail and bus stations, airports, shopping malls, banks, office buildings and foreign embassies.

"We have alerted everyone to take all necessary steps against any suspicious persons or acts," said Mizanur Rahman (search), Dhaka's police commissioner.

Police suspect Monday's bombings were carried out by Islamic militants who have been blamed for a series of bombings in recent months, police spokesman Mahmudul Kabir said.

He said the bombs were carried inside the courtrooms hidden inside large books.

In the city of Chandpur, 40 miles east of Dhaka (search), a 60-year-old man was killed and seven others wounded when two bombs went off at a court building, a police officer said. Police arrested two suspects at the scene, he said.

Almost simultaneously, two other bombs exploded at a courthouse in neighboring Laxmipur, killing an 80-year-old man and injuring at least 15 other people -- including a judge and a policeman -- according to police and doctors. Two suspects were detained at the scene, authorities said.

Another bomb went off at about the same time inside a court building in the city of Chittagong, injuring three people, witnesses and police said. Six suspects were arrested, Chittagong Police Commissioner Majedul Huq (search) told reporters.

Huq said police found three unexploded bombs after the blast in Chittagong, Bangladesh's second-largest city, 135 miles southeast of Dhaka.

No group claimed responsibility for the bomb attacks that have recently hit Bangladesh.