The Brazilian army swept into a crime-plagued Rio de Janeiro favela Wednesday, in its third major law enforcement operation since President Michel Temer put the military in charge of security in the former Olympic host city.
About 900 soldiers, backed by armored vehicles, aircraft and heavy engineering equipment were deployed in the western Rio favela of Vila Kennedy, the state's security command said.
Civil police "could make some arrests," and the military had authority to clear roads and restrict airspace, it said.
The UN High Commissioner on Human Rights, Zeid Ra'ad al Hussein, issued a statement in Geneva expressing concern over the decision to put the military in charge of security.
"The armed forces are not specialized in public security or investigation," he said. "I deplore calls by high-ranking army officials for measures amounting in effect to a preventive amnesty for any troops who may commit human rights violations."
Army troops had gone into Vila Kennedy on Saturday to remove street barricades erected by drug traffickers but they were rebuilt shortly after the troops left.
On Wednesday, an armored vehicle stopped at a small plaza in the favela and dozens of heavily armed soldiers poured out.
Other soldiers stopped riders on motorcycles to check their papers.
"When the military is here the situation is peaceful, but when they leave it turns into a hell again," said Rosanne Pinheiro, who was running a newsstand.
"The government should have other priorities like improving education so that young people don't see selling drugs as their only option," the 49-year-old said.
"I can't even remember all the times I had to hide because shooting broke out," she said.
Vila Kennedy was the scene of a previous military intervention on February 23 when some 3,200 troops were sent in to support the police.
That operation sparked protests by rights groups when troops took pictures of residents with their identity documents to determine whether they had criminal records.
Citing a breakdown in law and order, President Michel Temer ordered the army to take over the command of security in the whole of Rio state last month.
It was the first time the military has been put in charge of a state's security since the restoration of democracy in 1985.
"I urge the Government to ensure that security measures respect human rights standards, and effective measures are taken to prevent racial profiling and the criminalization of the poor," the UN High Commissioner for Human Rights said.