At least 25 people, including a police officer, have been killed in a drugs raid in a slum in Rio de Janeiro.
Dramatic footage from local television in Brazil showed heavily armed men fleeing police by leaping from roof to roof as a police helicopter flew low over the Jacarezinho favela.
Services on a subway line were temporarily suspended "due to intense shooting in the region," according to a statement from the operator.
Jacarezinho, one of the city’s most densely populated favelas with about 40,000 residents, is dominated by the Comando Vermelho, one of Brazil’s biggest criminal organisations.
The police consider Jacarezinho to be one of the group's headquarters.
Thursday's operation was aimed at investigating the recruitment of teenagers to hijack trains and commit other crimes, police said.
They said the criminal gang has a "warlike structure of soldiers equipped with rifles, grenades, bulletproof vests, pistols, camouflaged clothing and other military accessories".
The Candido Mendes University’s Public Safety Observatory said that at least 12 police operations in Rio state this year have resulted in three or more deaths.
Observatory director Silvio Ramos said Thursday’s raid was among the deadliest in the city’s recent history.
Many of them appear to violate a ruling by Brazil’s Supreme Court last year that ordered the police to suspend operations during the pandemic, restricting them to “absolutely exceptional” situations.
Rio police killed an average of more than five people a day during the first quarter of 2021, the most lethal start to a year since the state government began regularly releasing such data more than two decades ago, according to the Observatory.