By the BBC's Moazzem Hossain in Dhaka

Officials in Bangladesh say they have detained nearly 300 suspected criminals during a massive security operation in the capital, Dhaka.

Hundreds of policemen and members of paramilitary forces took part in the operation which officials say was aimed at rounding up listed criminals.

A reward of $260,000 has been offered to catch 23 top criminals

But students at Dhaka University complained police detained many innocent students and university employees during a raid in their dormitories and tortured them.

More than 200 police teams with the help of the paramilitary Bangladesh Rifles simultaneously raided student dormitories and possible hide-outs of criminals early on Friday morning.

It was the largest ever police drive against listed criminals in Dhaka since the present four-party coalition government led by Prime Minister Khaleda Zia came to power in October last year.

A police statement said 291 suspected criminals were detained during the raid.

The statement said among those detained were 48 listed criminals wanted in a number of criminal cases.

Torture allegations

However, students at Dhaka University say police rounded up nearly 50 students and employees from residential halls, whom they say were innocent.

They also complained that police tortured many students during the raid and blindfolded detained students.

Police officials declined to comment on these allegations.

Despite the successful arrests by police officials, crime reporters in Dhaka say the police raid has failed to arrest top criminals of the city.

A reporter for the Daily Jugantor newspaper in Dhaka, Fakhrul Alam Kanchan, said police offered a bounty of 15m taka ($260,000) against 23 top criminals, but none of them were among those arrested.

No progress

Prime Minister Khaleda Zia, who returned to power after a massive victory in last year's general election, declared that improving law and order would be her government's top priority.

But critics say the government has largely failed to achieve that goal.

In the last three months, the crime rate has gone up.

The lawlessness extended to an angry mob killing more than 30 suspected criminals on the streets of Dhaka.