President Luiz Inácio Lula da Silva of Brazil sent 800 army soldiers to the Alemão complex early Friday after police outposts in the city had come under fire from drug gang members. The death toll from the violence climbed to 41 on Friday, the police said, with nearly 100 cars and buses burned on major roadways, their passengers robbed and sometimes shot.

The deployment of soldiers indicated the government’s concern about the latest violence, analysts said, as well as its determination that Rio’s notorious gangs would not be allowed to prevail.

Image Credit... The New York Times

“It is not humanly possible that 99 percent continue to suffer in the hands of criminals,” Mr. da Silva said Friday at a news conference during a visit to Guiana. “Rio can be sure that the government will give all the help necessary.”

On Thursday, armored vehicles carrying police officers with assault rifles rolled over burning tires during an operation at Vila Cruzeiro, another gang-infested slum in the northern part of Rio. On Friday, the police declared they had “dominated” Vila Cruzeiro, although there were widespread reports that more than 100 gang members had escaped from the slum, prompting the deployment of the army troops.