DHAKA, Bangladesh

At least 50 people were injured on Sunday as riot police tear-gassed opposition activists to break up an anti- government rally in a park in central Dhaka, hospital sources said.

Bangladeshi police used batons and tear gas to block the main opposition party from staging a protest against the repeal of a law requiring the display of portraits of the nation's founder Sheikh Mujibur Rahman.

The police, who had set up barricades around the Osmany Oddayan park since dawn, tried to disperse a crowd of some 500 opposition activists, who retaliated by throwing pieces of bricks, witnesses said.

Several protesters, including former home minister Mohammad Nasim, sustained minor injuries, witnesses said.

Police took control of the park after the government banned gatherings or protests following the parliament's scrapping of the law which required portraits of Sheikh Mujibur to be displayed in public buildings.

Opposition leader Sheikh Hasina Wajed, who is Sheikh Mujibur's daughter, did not attend the protest but held an impromptu rally near her Awami League's downtown office.

She denounced the police action and called for a nationwide strike on April 6 as a show of anger against the government's "repressive" actions.

Police had arrested three opposition leaders, including former government ministers Motia Chowdhury and Saber Hossain Chowdhury, as they tried to go to the protest venue, said Naqib Uddin Ahmed, a spokesman for Sheikh Hasina.

Sheikh Hasina has blasted the repeal of the portraits law as a "disgrace" to Sheikh Mujibur, who led Bangladesh to independence from Pakistan in 1971 and was assassinated four years later.

The parliament, led by Prime Minister Khaleda Zia's Bangladesh Nationalist Party, on Thursday scrapped the law, passed under Sheikh Hasina's former government.

The repeal was signed into law on Saturday by President Badruddoza Chowhdury, officials said.

Khaleda Zia has proposed that a new bill be adopted that calls for the display of portraits both of Sheikh Mujibur and another independence hero, Ziaur Rahman, who was her husband. The plan has been rejected by the Awami League.

Ziaur Rahman, a military general, came to power after Sheikh Mujibur's death. He was also assassinated in an abortive coup in 1981.

The Awami League's 58 MPs have boycotted the 300-member parliament since the party was swept from power in an October 1 election, which it alleges was rigged. The party announced earlier in March that the MPs would also resign their positions, which would force new elections for those seats.

Sheikh Hasina has given no timetable for the resignations, but hinted the portrait bill might precipitate the move.

"We wanted to join the parliament provided a proper atmosphere was created by the ruling alliance, but with the scrapping of the law they (the government) have shut the door," a senior Awami League leader said.