Bangladesh today deployed paramilitary border guards to beef up security after a top Islamist opposition leader was sentenced to death, sparking nationwide riots that killed at least 42 people.

"Our troops were deployed in 15 troubled districts in aide of civil administration... BGB (Border Guard Bangladesh) has been kept alert so it could move immediately wherever they are required," BGB chief major General Aziz Ahmed said.

The violence broke out yesterday after 73-year-old Delwar Hossain Sayedee, vice-president of the Jamaat-e-Islami (JI), was sentenced to death by International Crimes Tribunal after he was found guilty of eight counts out of 20 involving rape, mass killings and atrocities during the nine-month freedom war against Pakistan in 1971.

A police spokesman, meanwhile, said law enforcement agencies were on high alert as Jamaat and Sayedee's supporters planned more protests today.