DHAKA: The number of people killed in clashes in Bangladesh over the conviction of Islamist leaders for war crimes rose to 53 on Friday as fresh violence erupted in the Muslim-majority nation.

Two people were killed when hundreds of pro-government supporters and followers of the rival Jamaat-e-Islami party battled each other with sticks in two northern districts of Gaibandha and Chapainawabganj, police chiefs told AFP.

Meanwhile, in the capital Dhaka, police fired rubber bullets and tear gas to break up Jamaat protests after the Islamists tried to stage marches following weekly prayers, leaving several people injured, police said.

Three policemen were also hurt in a homemade bomb attack by Jamaat student activists in the port city of Chittagong, deputy police chief Bonaj Kumar said.

On Thursday, violence flared across Bangladesh after Jamaat's vice president, Delwar Hossain Sayedee, was sentenced to death for murder, religious persecution and rape during the 1971 independence war.

The 73-year-old firebrand preacher was the third person to be convicted by a war crimes tribunal whose verdicts have been met by outrage from Islamists, who say the process is more about settling scores than delivering justice.

At least 35 people were killed in Thursday's unrest, according to an AFP toll compiled after talking to police in 15 districts where protests turned deadly.

Twenty-three of Thursday's dead were killed when police opened fire on thousands of rampaging Jamaat supporters who attacked law-enforcers with sticks and stones.

Jamaat, which has rejected the court's verdicts as politically motivated, put the death toll from Thursday's violence at 50, saying its "innocent" supporters were shot dead by police who "hunted them like birds".

According to Sultana Kamal, head of rights group Ain O Salish Kendra, it was the deadliest day of political violence since Bangladesh won independence from Pakistan in 1971.

Friday's killings brought the total number killed since the tribunal delivered its first verdict on January 21 to at least 53, according to the AFP tally and police.

The leader of the main opposition and two-time ex-prime minister, Khaleda Zia, appealed to the government to stop the "genocide" of Jamaat supporters, accusing police of brutality toward the Islamists.

Jamaat is a key ally of Zia's party, two of whose leaders are also on trial for war crimes. The opposition has called a three-day nationwide strike from Sunday to protest against the violence and the trials.

Neither police nor the government has commented on the opposition's charges of excessive force, but rights group chief Kamal accused Jamaat supporters of "terror" attacks on police.

Security was tightened around thousands of mosques for Friday weekly prayers. Police have banned a number of planned demonstrations at several trouble spots.

Security was also stepped up in Hindu villages and temples after Islamists torched and vandalised homes and places of worships in the southern Noakhali and Chittagong districts, killing one Hindu man, police said.

The war crimes tribunal has been shaken by controversies and allegations that it is targeting only the opposition with trumped-up charges.

Rights groups say its legal procedures fall short of international standards but the government argues the tribunal is independent and the trials are fair and is needed to heal the wounds of the war.

The government, which says the war claimed three million lives, accuses Jamaat leaders of being part of pro-Pakistani militias blamed for much of the 1971 carnage. Independent estimates put the death toll much lower at 300,000 to 500,000.