MONTREAL (AP) — The anti-doping laboratory in Mexico City has been shut down for up to six months for falling below international testing standards.

The World Anti-Doping Agency says the lab could be asked to review test results and re-analyze samples that recently tested positive.

It is the sixth of 34 WADA-accredited labs worldwide to be currently suspended from working.

The others are: Almaty, Kazakhstan; Lisbon, Portugal; Doha, Qatar; Madrid; and Bloemfontein, South Africa.

WADA says the suspension of Mexico City's accreditation could be extended by up to six more months if "non-conformities" are not addressed or new ones are found.