RIO DE JANEIRO (Reuters) - Police killed seven suspected drug traffickers in Rio de Janeiro on Wednesday, bringing to 33 the total number of deaths since the city’s worst recent outbreak of violence erupted over the weekend.

Three suspects were killed after they opened fire on police searching a slum in the north of the city for gang members linked to shooting down a police helicopter on Saturday, police spokesman Oderlei Santos said.

Four others were killed in separate operations in the city’s wealthier southern zone, police said.

State authorities have mobilized several thousand police to secure the city and search for drug traffickers who brought the helicopter down, killing three police officers.

Twenty-seven suspected gang members and three residents caught in cross-fire between gangs have been killed since Saturday in violence that has tarnished Rio’s image only a few weeks after it was awarded the 2016 Olympics.

The image of a dead suspected trafficker stuffed into a shopping cart and left on a road was carried by Brazilian and international newspapers on Wednesday, an example of the extreme gang violence and a sharp contrast to the scenes of joy on Copacabana beach broadcast around the world this month when Rio won the Olympics.

Residents in one slum near where the helicopter crashed in flames left their homes on Tuesday night and were afraid to return because of rumors a gang from another slum was planning an invasion.

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“Everyone is afraid of going back to their homes, it’s better to stay on the street,” one male resident who asked not to be identified told reporters.

President Luiz Inacio Lula da Silva has offered Rio state nearly $60 million over six months to help combat the violence.

Rio’s police often respond brutally to drug gangs, wounding and killing innocent residents as a result of tactics that have been consistently condemned by human rights groups.

The police last year killed more than 1,100 suspects described as “resisting arrest.” Residents killed in police raids are routinely labeled as suspected criminals, without investigations to back up the charge.