Police attempts to recapture a drug trafficker who escaped from a Brazilian hospital have led to deadly gunbattles in the slums of Rio de Janeiro.

The O Globo newspaper says 10 people have been killed and about 50 schools have been shuttered over the past nine days. Police would not immediately confirm the death toll.

Nicolas Labre Pereira, nicknamed "Fat Family," was freed on June 19 when assailants stormed one of the hospitals recommended for tourists traveling to the Olympic Games.

The violence is adding to worries about safety in Rio during the Olympics, which begin in August.

Last weekend, an off-duty bodyguard for Rio's mayor was shot dead in an apparent mugging. Also, a 34-year-old doctor was killed in her car on a main expressway.