Russia is once again in danger of being banned from next year's Olympics after the World Anti-Doping Agency (WADA) revealed that historical data supplied by the country's anti-doping authority contained "inconsistencies."

And WADA gives Russia three weeks to explain the "inconsistencies".

"There's evidence this data has been deleted," said Jonathan Taylor, chairman of WADA's compliance panel, according to BBC Sport.

"We need to understand from the Russian authorities what their explanation is."

Russia stands to be declared non-compliant by WADA if it fails to explain why evidence of some positive tests handed over by a whistleblower does not show up in data provided by Moscow's anti-doping laboratory in January.

IAAF maintains a ban on Russian athletics federation

In another blow on Monday, the International Association of Athletics Federations (IAAF) maintained a ban on the Russian athletics federation pending analysis of the data.

IAAF President Sebastian Coe said after a meeting in Doha that his organization's anti-doping taskforce had given "the strongest recommendation we've probably had" that Russian should remain suspended from track and field.

Though the Russian federation has been banned since November 2015, athletes from Russia have been competing for years as neutrals and 118 are due to participate in the World Athletics Championships which get underway in the Qatari capital on Friday.

If Russia challenges an eventual wider suspension by WADA, the case will go to the Swiss-based Court of Arbitration for Sport, whose decision will be binding on sports bodies including the International Olympic Committee (IOC).

Explaining WADA's new concerns, the agency's director general Olivier Niggli told AFP after an executive committee meeting in Tokyo: "Forensic experts have looked at what we got from whistleblowers, what we got from Russia and they noticed some inconsistencies.

"Then they studied the differences and this came to a situation where there are some questions that need to be asked and answered."

WADA has previously warned that it would take the "most stringent sanctions" if any of the data was found to have been tampered with.

Russia's Olympic participation at risk, says top Russian sports official

The head of Russia's Olympic Committee said Monday that his country's participation at the 2020 Tokyo Olympics was at risk over the alleged manipulation of anti-doping laboratory data.

Stanislav Pozdnyakov, the president of Russia's Olympic Committee, said the situation was "very serious" and could jeopardize Russia's Olympic participation.

"We have spent vast diplomatic efforts to regain the trust of the international sports community and for Russian athletes to have the right to take part in Olympics without any restrictions," Pozdnyakov said in a statement.

"But now we again run the risk of facing sanctions for reasons with which we have nothing to do."

Authorized neutral athletes

The IOC put restrictions on Russia's participation at the last two Olympic Games.

Russia was barred from the PyeongChang Winter Games last year as punishment for alleged state-sponsored doping at the 2014 Sochi Olympics.

However, some Russians with no history of doping were cleared to compete as neutrals, in short of Authorized Neutral Athletes (ANA).

The IOC chose not to ban all Russian athletes from the 2016 Olympics in Rio de Janeiro after a WADA-commissioned report revealed a state-backed doping program across many sports.

Getting out of the vicious circle or not?

Russia has three months to respond to WADA's concerns, the head of Russian Anti-doing Agency (RUSADA) and the Kremlin said.

When contacted by Reuters, RUSADA director general Yuri Ganus would not comment on the nature of the inconsistencies uncovered by WADA. He said the laboratory's database had not been under the agency's jurisdiction.

"I am profoundly convinced that new people are needed to get out of this anti-doping crisis," Ganus said. "We need to get out of this vicious circle."

Kremlin spokesman Dmitry Peskov said the Kremlin was aware of the issue, but that it was a matter for the country's sports authorities.

RUSADA was reinstated by WADA last year after the Russian agency served a suspension of nearly three years over evidence of mass doping in Russian athletics. The handover of laboratory data to WADA had been a condition for its reinstatement.

Russian Sports Minister Pavel Kolobkov said the ministry would cooperate with WADA in determining what was wrong with the data.

"We were told that the database submitted to WADA is slightly different that from the copy that WADA experts took in Moscow in 2019," Kolobkov said in a statement.

"Experts in the field of digital technology from both sides will determine what these discrepancies are and what they are linked to."

(With input from AFP and Reuters)