Supporters of Bangladesh's opposition parties have clashed with security forces in Dhaka ahead of the country's general election next week.
Police said two people were killed as protesters defied a ban on rallies.
The opposition is demanding that Prime Minister Sheikh Hasina steps down and a neutral government is installed before the election.
The government has rejected the demand, saying the elections are a constitutional necessity.
Police fired water cannon and rubber bullets at protesters who threw stones and homemade bombs, according to reports.
The leader of the main opposition Bangladesh Nationalist Party (BNP), Khaleda Zia, had called for a march on the capital, Dhaka, in defiance of a police ban, to protest against what she calls the "farcical" election.
Police surrounded her home on Sunday in an apparent bid to stop her from addressing the demonstration. They deny holding her under virtual house arrest.
"The government is undemocratic and illegal. It should step down immediately," Ms Zia, a former prime minister of Bangladesh, told reporters outside.
One person was killed as police opened fire on protesters in the centre of the city, and a guard was killed in a blast at a train station, police said.
Supporters of the governing Awami League - armed with sticks and rocks - also clashed with opposition activists outside the Supreme Court.
Local media reported that hundreds of people had been detained in recent days as part of a nationwide crackdown ahead of the 5 January elections, which the opposition is boycotting.
The BNP and its allies have staged weeks of deadly protests, strikes and transport blockades to try to force the prime minister to resign. Scores of people have been killed.
The opposition fears the government will rig the polls if it remains in power.
Caretaker governments previously oversaw elections, but Ms Hasina scrapped the arrangement in 2011.
A series of rulings against the BNP's Islamist ally, Jamaat-e-Islam, have also led to violent protests across Bangladesh, with many people killed.