LAUSANNE, Switzerland (AP) — The IOC is warning Brazilian organizers about the pace of progress for the 2016 Games in Rio de Janeiro.

The IOC says Tuesday they must attack the project "with all vigor" to ensure that the first Olympics in South America are a success.

With the games less than four years away, Rio organizers briefed the International Olympic Committee executive board on their preparations amid leadership changes and uncertainty about the budget and some sports venue locations.

Rio brought its new chief executive, Sidney Levy, to the IOC headquarters in Lausanne, Switzerland. He'll over the post in January. He replaces Leonardo Gryner, who becomes the chief operations officer.