France's anti-doping agency says cycling great Lance Armstrong violated its rules with his behaviour during a recent drug test and that the seven-time Tour de France champion may be punished.

French doctors said they tested Armstrong's hair, urine and blood on March 17 while the American rider was training in Beaulieu-sur-Mer in southern France and found no traces of drugs. But the anti-doping agency, known as AFLD, has suggested Armstrong may have tried to evade the test, and sent a report on the incident to cycling's governing body and the World Anti-Doping Agency.

The AFLD said in a statement Thursday that a doctor charged with testing Armstrong says the cyclist "did not respect the obligation to remain under the direct and permanent observation" of the tester.

The AFLD said it can impose sanctions on Armstrong, but didn't indicate what they would be.

At question is a 20-minute delay when Armstrong says the tester agreed to let him shower while his assistants checked the tester's credentials.

Armstrong, who is hoping to win an eighth Tour de France title in July, issued a statement on Tuesday denying any wrongdoing. He also lashed out at French anti-doping officials.

"I did not try to evade or delay the testing process that day," Armstrong said.

"This is just another example of the improper behaviour by the French laboratory and the French anti-doping organizations. I am sorry that they are disappointed that all the tests were negative, but I do not use any prohibited drugs or substances."

A spokesman for the International Cycling Union (UCI) has said the organization doesn't have any jurisdiction in the matter. Testing of hair samples is allowed under French law, but is not recognized by WADA or the UCI.

Armstrong said he had returned from a ride to find the tester at his house, identifying himself as a representative of a French lab.

Although he has submitted to numerous tests conducted by sports doping authorities, Armstrong said he was unaware the French government and labs could conduct them on their own.

Once they checked the sample collector's credentials with the UCI, Armstrong said he willingly gave the samples, although he has previously complained the hair sample collection "butchered" his haircut.

"I had no idea who this guy was or whether he was telling the truth," Armstrong said. "We asked the tester for evidence of his authority. We looked at his papers but they were far from clear or impressive and we still had significant questions about who he was or for whom he worked."

Armstrong said he wanted to make sure the tester "wasn't just some French guy with a backpack and some equipment to take my blood and urine."

With files from the Associated Press