Bangladesh police fired rubber bullets and tear gas at stone-throwing opposition party supporters blocking major roads in the capital Dhaka on Saturday to demand the prime minister’s resignation.

The main opposition party, in disarray since its leader Khaleda Zia was jailed in 2018 on graft charges, has held bigger protest rallies in recent months, including one on Friday, drawing tens of thousands of supporters amid anger over the cost of living.

The Bangladesh Nationalist Party has been calling for Prime Minister Sheikh Hasina to step down and for the next election, due in January 2024, to be held under a neutral caretaker government – a demand her government has rejected.

BNP activists set fire to buses and exploded petrol bombs, according to police and media.

“Our force was attacked without any reason. They were only trying to ease the traffic flow,” said Faruq Ahmed, a spokesman for the Dhaka Metropolitan Police.

“We had to fire tear gas and rubber bullets to control the situation,” he added.

The BNP said dozens of its supporters were injured. Police said at least 20 officers were hurt in the clashes.

At least 90 people were arrested, while two senior BNP leaders were taken into police custody and later freed, police said.

Senior BNP leader Abdul Moyeen Khan denounced the police action as an “injustice”.

“Today’s rampant action … only confirmed the autocratic nature of the ruling regime and fully exposes their motives to remain in power through a rigged election,” he told Reuters.

He said more than 100 demonstrators had been arrested and scores were severely beaten up, while police were seeking to curtail people’s “fundamental right of association”.

Western governments and rights groups have criticised the government for cracking down on anti-government protests.

In May, the United States said it would restrict visas for Bangladeshis who undermine the democratic process at home.

Concern flared after accusations of vote-rigging and suppressing the opposition marred elections in 2014 and 2018. Hasina’s government has denied the charges.

Hasina, who has maintained tight control since coming to power in 2009, has been accused of authoritarianism, human rights violations, cracking down on free speech and suppressing dissent while jailing her critics.

Hasina’s arch rival, former premier Khaleda, was allowed to stay at home in Dhaka under a special provision since the COVID-19 pandemic but was barred from political activity.