An attempted invasion of Rio de Janeiro's largest favela by rival drug traffickers on Good Friday left at least three civilians dead and wounded scores of others.

In the shootout that followed, two residents were killed by stray bullets, 27-year-old Welington da Silva and 24-year-old Fabiana dos Santos Oliveira.

Another seven locals were taken to a nearby hospital, two seriously injured.

"This is exactly what we were trying to avoid," said local police commander Renato Hottz. "Unfortunately, we were unable to allay the violence."

The favela has been on high alert since February when a former drug lord escaped from prison.

At the time it was widely publicised that Eduíno Eustáquio de Araúju - also known as Dudu - would try to seize control of the drugs market from Rocinha's current boss, 23-year-old Luciano Barbosa da Silva, or Lulu.

"Their objective is to get in and kill all of the rivals of Dudu's faction within the Comando Vermelho (Red Command)." added Hottz.

Rocinha is the principal point for drug trafficking in the city. According to police, the trade generates about R$10 million each week.

A woman was also killed on a nearby main road when traffickers from nearby Vidigal district tried to steal her car for use in the invasion.

Thirty-eight-year old Telma Veloso Pinto was driving home with her son and nephew when they were ambushed.

The traffickers opened fire when she didn't stop, killing her and wounding her 16-year-old son in the leg.

However, the second attempted invasion in a week failed, and police arrested five suspected traffickers.

An extra 380 police are now occupying the two communities. But despite this violence broke out again on Friday evening.

According to early reports one police officer was killed in a shootout with traffickers.

Rio's mayor, Cesar Maia, blamed the escalating violence on state security minister, and aspiring president, Anthony Garotinho.

"Everyday it becomes clearer that the security department is losing more than a few battles: It is losing the war," he told the O Dia newspaper.

"Garotinho has put on several performances: Operation asphyxiate, [police] occupation, [making] contact with community leaders, but the facts show that none of these are anything more than theatrics."

Since rumours of an invasion surfaced in February, the community has been relatively quiet.

Tour guides in Rio de Janerio, Brazils' tourism capital, who had avoided parts of the favela, were operating their usual programs.

"It seems to have quietened down," Marcelo Armstrong, the head of Favela Tour - a company which runs excursions in the community - said on Wednesday in Rocinha.

"I hope that it has anyway," he added.

Less than 48 hours later the calm had been replaced by uncertainty and the sound of gunfire once more.