The request will be sent by Rio de Janeiro Governor Francisco Dornelles to interim President Michel Temer in the coming days, according to Rio security secretary Jose Mariano Beltrame on Thursday, reports Xinhua.
If the plan is approved, the armed forces will have the same powers as police during the Olympics.
A federal government-backed report has also recommended that armed forces occupy six shantytowns — known locally as favelas — in strategic areas close to Games venues.
“The request for external forces is so that the police can go about their task of taking care of (law enforcement around) the city,” Beltrame said on Thursday.
It is understood up to 15,000 military personnel will be called upon for the Games, which will run from August 5 to 21.
An additional 9,300 members of Brazil’s national security force will be charged with ensuring safety and public order inside arenas and Games venues.
Thursday’s announcement came as new figures showed a sharp rise in Rio’s murder rate this year.
According to Brazil’s ISP public security institute, there were 1,715 homicides from January to April compared to 1,486 during the same period last year.
There were 471 homicides last month compared to 339 in April 2015.
“Apart from some exceptions everything is under control, but that doesn’t mean that we are not on alert,” Brazil’s defence minister Raul Jungmann said.