Brazil's anti-doping laboratory in Rio de Janeiro has lost its accreditation six weeks before the start of the Olympics. World sport has been hit by a series of doping scandals.
The World Anti-Doping Agency (WADA) said on Friday it suspended Rio's drug testing laboratory after it found "non-conformity" with international testing standards.
The decision means Rio's Ladetec will be unable to test blood and urine samples of athletes competing in the Olympics and Paralympics.
The suspension is another blow to Rio's Olympic organizers, coming on top of months of political crisis and financial troubles that have put the city's readiness to host the games into question.
Athletes' samples will still be tested for doping at laboratories in other countries, WADA said, without specifying where.
"The agency will ensure that, for the time being, samples that would have been intended for the laboratory will be transported securely, promptly and with a demonstrable chain of custody to another WADA-accredited laboratory worldwide," the anti-doping body said in a statement.
"This will ensure that there are no gaps in the antí-doping sample analysis procedures and that the integrity of the samples is fully maintained," it added.
The Rio laboratory has 21 days as of Wednesday, when it was notified, to appeal.
"The suspension will only be lifted by WADA when the laboratory is operating optimally," said Olivier Niggli, the incoming director general of the agency. "WADA will work closely with the Rio laboratory to resolve the identified issue."
The International Olympic Committee (IOC) and WADA have been hit by multiple doping scandals in recent months, including a decision to ban Russia's track and field team from the Olympics over an expansive doping scandal.
The doping crisis has led to questions over integrity of world sport.
Niggili vowed to have a robust anti-doping test program in place for the August 5-21 Olympic Games.
"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," he said.
WADA will now send a team to review the Rio laboratory and make recommendations on its accreditation.
The Rio laboratory said in response to the suspension that it expects to resume testing after the WADA technical committee reviews the facility next month. It said it could restart testing in time for the Olympics.
Cw/jm (AFP, AP, dpa, Reuters)