Rio's anti-doping laboratory has been suspended by the World Anti-Doping Agency just six weeks before the Brazilian city hosts the Olympic Games.
The decision adds to concerns about Rio's readiness to host the global sporting event in August as public services suffer amid a crisis in state finances.
"The suspension will only be lifted by WADA when the laboratory is operating optimally," Olivier Niggli, the incoming director general of the agency, said in a statement, without providing details about the problems at the lab.
"The best solution will be put in place to ensure that sample analysis for the Rio Olympic and Paralympic Games is robust," the statement said.
Doping is high on the agenda ahead of the Rio Games, the first Olympics to be held in South America, after the Russian team was suspended from athletics events there because of doping allegations in track and field.
The Rio lab's six-month provisional suspension is subject to an appeal during a 21-day window that started yesterday, when WADA first informed the laboratory of its decision.
Samples intended for analysis at the premises will be redirected to another WADA-accredited laboratory, the agency said, without saying where.
Rio's is the sixth laboratory to be sanctioned by Wada in recent months.
Madrid, Bloemfontein, Beijing and Lisbon have also been suspended from Wada-related activities, while Moscow's laboratory had its accreditation revoked in April.
"Athletes can have confidence that the suspension will only be lifted by Wada when the laboratory is operating optimally; and that the best solution will be put in place to ensure that sample analysis for the Rio Olympic and Paralympic Games is robust," said Wada's incoming director general Olivier Niggli.
The decision leaves 29 Wada-accredited labs in the world.
-Reuters & BBC