LONDON — The IOC expressed confidence Tuesday that Brazil will deliver a safe Olympics in 2016 despite the weekend violence between rival drug gangs that killed 21 people in Rio de Janeiro.

The firefight, which brought down a police helicopter, took place in the Morro dos Macacos ("Monkey Hill") slum about five miles southwest of one of the zones where Olympic events will be held.

The violence came two weeks after the International Olympic Committee voted to award the 2016 Games to Rio, taking the event to South America for the first time. Rio defeated Madrid, Tokyo and Chicago.

"Security is of course a very important aspect of any Olympic Games no matter where it is in the world," IOC spokesman Mark Adams said. "This is of course entirely under the national, regional and city authorities.

"We have confidence in their capacity to deliver a safe games in seven years' time."

Several IOC members said the violence in Rio brought back memories of the bomb attacks that rocked London a day after the British capital was awarded the 2012 Olympics in 2005 in Singapore.

Fifty-two people were killed when four suicide bombers attacked London's subway and bus network on July 7, 2005.

"In a sense it's a little bit like what happened after Singapore," senior Canadian member Dick Pound said. "You don't reach a conclusion on an event seven years away on the basis of some uncomfortable stuff in the interim."

Executive board member Gerhard Heiberg of Norway said there was no reason to be overly concerned.

"There are seven years to go," he said. "This came now. Hopefully they can clean that up. I'm not too worried."

In an evaluation report issued a month before Rio's victory in Copenhagen, the IOC said Rio faced "safety challenges" but that community police programs had produced "positive results" in reducing crime.

"IOC members voted on the basis of an evaluation commission report that invited them to disregard (crime) as a serious factor," Pound said. "It was basically telling the membership not to worry about that."

Security is also an issue for the 2014 World Cup in Brazil.

"We'll do anything it takes and make all necessary sacrifices so we can clean up the mess that these people are imposing on Brazil," Brazilian President Luiz Inacio Lula da Silva said Monday in Sao Paulo.