The World Anti-Doping Agency (WADA) has announced that it has suspended the accreditation of the Brazilian Doping Control Laboratory, just six weeks before the start of the Olympic Games in Brazil.
WADA said the ban was imposed because the laboratory in Rio de Janeiro failed to comply with international standards.
Rio 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.
The suspension on the Rio laboratory took effect on June 22 and prohibits the laboratory from carrying out all anti-doping analyses on urine and blood samples.
The lab may appeal against the decision to the Court of Arbitration for Sport within 21 days of receipt of notice.