Brazil's southeast city of Rio de Janeiro Friday opened the bidding for two infrastructure projects in the lead-up to the 2016 Olympic Games, Mayor Eduardo Paes said.

Paes said in a press release that the projects are part of the Diodoro Sports Complex that will host some 11 Olympic competitions.

The works, which are estimated to cost 804 million reals (about 359 million US dollars) and are expected to get underway in September, include the renovation of the complex also known as Sport City.

The projects also call for the construction of three new stadiums and the renovation of four others, as well as the installation of three temporary venues, whose delay has been a source of concern for the International Olympic Committee (IOC).

Acknowledging that preparing the bidding process took longer than expected, Paes said he expects the works to be concluded by the first half of 2016, as the games begin Aug. 5.

He pledged, however, to have the projects finished in time for the events.

Sport City will host nine different Olympic disciplines, including basketball, cycling, fencing, field hockey and rugby, as well as four disciplines as part of the Paralympic Games, which will take place Sept. 7-18.

The complex, originally built by the city to host several events of the 2007 Pan-American Games, features a 15,000-seat multipurpose arena for basketball and artistic gymnastics, a 5,000- seat aquatic complex, and a 1,500-seat velodrome.

The 21st Olympic Games will gather the world's top athletes in 28 different sports in Rio from Aug. 5 to 21.