Three stations on a new express bus corridor connecting Rio de Janeiro's international airport to Olympic Park were closed after a shootout between police and drug gangs.

Authorities said the Madureira, Mercadao and Otaviano stations were shut for almost an hour on Saturday after traffickers opened fire on a police car near the Serrinha favela in Rio's north.

The stations are part of the newly opened Transcarioca bus line, built for next month's Olympic Games.

No injuries were reported from the exchange of fire and there were no arrests.

Authorities in Rio are battling to contain a rise in violent crime as the city prepares for the August 5-21 Olympics.

In the first five months of 2016, the number of homicides in Rio rose by 18 percent to 1,870 compared to the same period in 2012 when killings reached their lowest rates of the past decade.

Brazil will deploy 88,000 soldiers and police during the August 5-21 Games, more than double the number used at the London 2012 Olympics.