Police shot a mugger near the stadium where the Rio Olympics opening ceremony took place and a woman was killed close to another Olympic site, police said yesterday.

The violence on Friday highlighted the task facing an unprecedented force of 85,000 soldiers and police deployed to secure the Olympics.

Rio police said in a statement that a man was mugging people near the Maracana stadium when he was intercepted by one of the police officers sent from another area of Brazil to Rio as part of the huge reinforcements.

"The man was carrying out assaults when a military police officer... shot him," the statement said.

Hours earlier, an architect was killed while driving by one of the main entrances to the Olympic Boulevard.