Protests have taken place across Brazil over the management of the Covid-19 crisis by the government of President Jair Bolsonaro.
In the capital, Brasilia, thousands gathered in front of Congress calling for the president's impeachment, and demanding more vaccines.
Demonstrations took place in other major cities, including Rio de Janeiro.
Mr Bolsonaro's popularity has plummeted over his response to the pandemic.
Brazil has registered nearly 460,000 deaths - the second-highest toll in the world after the US. It also has the third-highest number of coronavirus cases at more than 16 million.
Saturday's protests piled further pressure on Mr Bolsonaro as Brazil's Senate holds an inquiry into his government's handling of the pandemic and the slow roll-out of the vaccine programme.
Opposition parties, trade unions and social movements accuse Mr Bolsonaro of stalling the programme and disregarding the consequences.
The high number of cases has brought the country's health system to the verge of collapse.
The far-right leader has consistently opposed lockdown measures, arguing that the damage to the economy would be worse than the effects of the coronavirus itself. He has also told Brazilians to "stop whining" about the situation.
In Brasilia, protesters marched alongside a giant plastic doll of the president. Placards demanded his impeachment and called for more vaccines and emergency financial aid. There were also calls to better protect indigenous people and to stop deforestation of the Amazon.
In Recife, police fired rubber bullets and tear gas at protesters who tried to march down a closed road, local media reported.
In some cities, demonstrators laid thousands of symbolic crosses in tribute to those who died in the pandemic.
On Thursday, the head of Brazil's prestigious Butantan Institute told a Senate committee that President Bolsonaro's actions delayed the start of the vaccination programme, the Spanish news agency Efe reports.
Dr Dimas Covas said that in August last year, Butantan offered to supply the government with 100 million doses of the CoronaVac vaccine, which the institute manufactures under licence from China's Sinovac. He said the proposal included a pledge to deliver the first five million doses by the beginning of December.