Three Russian speedskaters face long doping bans after testing positive for meldonium.

World-record holder Pavel Kulizhnikov faces a possible life ban for a second offense after he previously served a doping ban in 2012 for methylhexanamine. Two other Russian speedskaters, Olympic relay gold medalist Semyon Elistratov and short-track racer Ekaterina Konstantinova, face potential four-year bans for a first offense.

The International Skating Union said Friday that tests of their "B" samples matched the initial positive tests for meldonium.

The ISU did not provide an update on former European ice dance champion Ekaterina Bobrova, who won Olympic team gold for Russia in 2014.

The ISU said last week that Bobrova's "A" sample was positive for meldonium, a drug that was added to the banned list this year.

The World Anti-Doping Agency told The Associated Press it had registered 102 failed tests for meldonium worldwide since Jan. 1. That marks a sharp fall in the number of new cases, with just three registered in the last seven days.

So far, at least 20 athletes have been suspended as a result, ranging from Maria Sharapova to an Olympic wrestling medalist and a former world champion runner.

Most of the known cases so far involve Russian athletes. On Wednesday, Russian President Vladimir Putin berated sports officials for what he said was a slow response to WADA's announcement in September that meldonium would be banned for 2016.

"Our sports leaders showed a lack of understanding concerning the relevance of these issues, and were unable to update the corresponding lists quickly enough," he said, according to a transcript on the Kremlin website.

Putin also criticized Russian officials for failing to determine how long the substance takes to leave the body. Several athletes facing meldonium charges have said they stopped taking the drug before Jan. 1, suggesting it may have remained in their system for longer than expected.