LAUSANNE, Switzerland (AP) — Four Russians have been allowed to resume competing in skeleton even though they are under investigation for alleged doping rule breaches at the 2014 Winter Olympics, the International Bobsled and Skeleton Federation said Sunday.

The IBSF had issued provisional suspensions to the four, including Olympic gold medalist Alexander Tretyakov, on Dec. 30 after the International Olympic Committee opened an investigation into apparent tampering with drug test samples.

However, the IBSF said that a hearing on Tuesday found there is so far "not sufficient evidence" to justify provisional suspensions, which keep athletes out of competition for the duration of a doping investigation.

The IBSF's doping hearing panel says its ruling doesn't affect the ongoing IOC investigation and "invites the IOC to share any outcome of its investigation with the IBSF in order to potentially reconsider the position of the athletes."

For the first time, the IBSF has also identified the competitors involved. Besides Tretyakov, they are Elena Nikitina, Olga Potylitsina and Maria Orlova, who finished third, fifth and sixth respectively at the 2014 Olympics.

The accusations against them followed the publication of World Anti-Doping Agency investigator Richard McLaren's report accusing Russia of operating a state-sponsored doping system in which top Russian athletes' samples were secretly swapped for clean ones during the 2014 Olympics in the Russian city of Sochi.

All four of the skeleton racers under investigation are now cleared to resume competing immediately at World Cup events and next month's world championships, which were moved from Sochi to Koenigsee in Germany after athletes from around the world protested the choice of Russia as host.