Interim Brazilian President Michel Temer inaugurated a much-anticipated subway line in Rio de Janeiro on Saturday, just days before the opening of the Olympics in the city.

Rio's new metro Line 4, which will be a major legacy of the games, links the city's tourism district with the western Barra da Tijuca neighborhood, where many of the Olympic events are slated to take place.

Olympic organizers had worried that the new 16-km line might not be ready in time for the opening of the games on Friday, as construction was plagued by constant delays, leading to critical congestion on city streets.

"The Olympic Games represented an excuse to improve all of Rio de Janeiro," Temer told an inauguration ceremony of the six-stop line, which is expected to serve more than 300,000 passengers a day.

During the Olympics and Paralympics, the line will be reserved for the exclusive use of the "Olympic family," officials said, meaning for athletes, organizers, and others with special access.

The key Olympic transport line features Chinese-made trains and will be operated during the games by the Chinese.

Chinese trains are already running on the city's Line 1 and Line 2.

Earlier this month, Rio State Transportation Secretary Rodrigo Vieira told Xinhua, "Line 4 will contribute to making the Rio Olympic Games the best in history and will become an important legacy for the city, improving the quality of life of the people who live here."