12/04/2012 10:12 EST | Updated 02/03/2013 05:12 EST

IOC tells Rio organizers that 'time is ticking' in preparation for 2016 Olympics

LAUSANNE, Switzerland - With concern mounting about the pace of progress for the 2016 Games in Rio de Janeiro, the IOC warned Brazilian organizers Tuesday that "time is ticking" and they must attack the project "with all vigour" 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 continuing uncertainty about the budget and location of some sports venues.

Rio brought its new chief executive, Sidney Levy, who will take over the post in January. He will replace Leonardo Gryner, who becomes the chief operations officer.

"Our message remains: There is time, but time is ticking, and they need to carry on attacking this one with all vigour," IOC spokesman Mark Adams said in an unusually blunt public statement about an Olympic organizing committee.

The meeting came just a few weeks after IOC officials were in Rio for a debriefing with organizers of this year's highly successful London Olympics. While London's seven-year preparations for the games went off without any major crises, the IOC is concerned that Rio organizers are still facing major challenges.

Carlos Nuzman, head of the Rio organizing committee, said everything remains on schedule.

"We are in a very good comfortable situation," he said. "It's important we work as a team — the IOC, the organizing committee and the government. I think we are in a very good way."

Rio recently announced the rugby venue won't be built where it was originally planned, and there is still uncertainty over the location of the field hockey arena. The land where the golf course will be constructed remains the source of a legal dispute.

"We went through some of the venues that still need to be finalized," Adams said. "There is no kind of great concern. There is nothing new."

Adams said the IOC asked organizers about the Brazilian economy, which experienced disappointing growth figures for the third quarter.

While Rio officials still don't have an exact figure for the cost of the games, Nuzman said the budget would be announced next year. Billions of dollars are being spent on venues and infrastructure upgrades.

"We are expecting (the budget) any time," Adams said. "I don't think there is any great concern about that. It is still within the timescale we're expecting."

Nuzman hailed Brazilian President Dilma Rousseff's decision last week to veto part of a bill that will give a greater share of royalty revenues from the country's vast oil fields to non-producing states.

Rio de Janeiro state officials had warned that without a veto, the measure would deprive Rio of $1.7 billion in 2013 alone, endangering preparations for the 2014 World Cup and the 2016 Olympics.

"We have a fantastic decision from our president," Nuzman said. "It gives Rio a recognition of the rights that they have."