Story highlights The World Anti-Doping Agency says Brazil team didn't provide enough samples in month before Games

Russian team has previously been at the center of doping questions at this year's Games

(CNN) Brazil's Olympic team gave about a third as many samples as normally expected in the crucial month before the games began, CNN can reveal -- an "unacceptable practice" according to the world anti-doping watchdog.

The host nation has already been sanctioned by the World Anti-Doping Agency, or WADA, over concerns its testing of its own athletes ahead of the Games was delayed, and perhaps compromised. Yet CNN has learned there may not actually be enough samples to test to give the team -- the second largest at the games -- a clean record for July. This is because Brazilian athletes gave a significantly reduced number of samples in the first three weeks of July.

The World Anti-Doping Agency said the gap in samples collected by Brazil's anti-doping agency was "unacceptable practice ... particularly at such a crucial time before the Olympic Games." It added: "These numbers are not in line with an effective program." The spokesman said it may have left a "big gap."

A spokesman for the Brazilian Ministry of Sport, Paulo Rossi, told CNN the Brazilian team of 477 athletes gave a total of 110 samples in the first 24 days of July. He described the average amount they would be expected to give in that period "as I think about 300," or possibly less.

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