RIO DE JANEIRO: Seven people, including a boy of 14, have been killed in continuing violence between army-backed police units and Rio de Janeiro's criminal gangs, reports said Thursday. In the latest crackdown, soldiers and marines in camouflage and carrying rifles could be seen searching people as they came in and out of two poor neighborhoods, known as favelas, within the posh Copacabana beach area. The military, which was put in charge of security in Rio de Janeiro earlier this year, said the operation involved 1,800 troops and 50 police officers. Their goal was to remove roadblocks put up by gangs and to "check up on reports of criminal activity and other illicit conduct."

The operation caused large rush-hour traffic jams in the busy seaside area, but there was no sign of shooting incidents.

On Wednesday, in a separate operation conducted in the sprawling network of favelas known as the Mare, police backed by armored vehicles clashed with drug traffickers.

Six people carrying weapons, ammunition and drugs were killed, according to the G1 news site. A 14-year-old schoolboy who was hit by a stray bullet died of his wound later that night, G1 reported.

"The boy was late and was going to school when he was shot," municipal schools official Fatima Barros said on Globo television.

Brazil's second biggest city, which hosted the Olympics in 2016, is suffering from a cocktail of surging violent crime and financial disarray.