Bangladesh police fired rubber bullets and tear gas to disperse stone-throwing crowds blockading major roads in the capital Dhaka on July 29 in the latest protest demanding the prime minister's resignation.
The opposition Bangladesh Nationalist Party (BNP) and its allies have staged a series of protests since last year demanding Sheikh Hasina step down and allow a caretaker government to oversee elections due next January.
Clashes erupted in several locations when police moved in to clear thousands of people who gathered in the morning to block traffic on key arterials around the city.
"Some officers were injured," Dhaka Metropolitan Police spokesman Faruk Hossain told AFP. "We fired tear gas and rubber bullets."
At least four protest sites around the city saw clashes between police and protesters, Mr. Hossain said, with 20 officers injured and 90 protesters arrested.
AFP journalists at one protest site in Dholaikhal, an old neighbourhood now a hub for automotive repair shops, witnessed protesters retaliate by throwing rocks at riot police and their vehicles.
Bacchu Mia, a police inspector at the Dhaka Medical College Hospital, told AFP that six protesters had been admitted to the hospital with injuries.
Senior BNP leaders Goyeshwar Roy and Amanullah Aman had been taken into police custody but had not been formally arrested, Mr. Hossain said.
Transport links between the capital and other parts of the country were badly disrupted, with trucks and buses stuck in gridlock.
Ms. Hasina's Awami League has ruled Bangladesh since 2009 and has been accused of human rights abuses, corruption and creeping authoritarianism.
Demonstrations led by the BNP have become increasingly common since the start of the year, with rallies this month drawing tens of thousands of people to the streets.
Police arrested at least 500 opposition activists ahead of a rally outside the party's headquarters this week.
Western governments have expressed concern over the political climate in Bangladesh, where the ruling party dominates the legislature and runs it virtually as a rubber stamp.
Her security forces are accused of detaining tens of thousands of opposition activists, killing hundreds in extrajudicial encounters and disappearing hundreds of leaders and supporters.
The elite Rapid Action Battalion (RAB) security force and seven of its senior officers were sanctioned by Washington in 2021 in response to those alleged rights abuses.
The BNP's leader Khaleda Zia, a two-time premier and old foe of Ms. Hasina's, is effectively under house arrest after a conviction on graft charges.