Ryan Murphy casts doubt on whether a Russian swimmer beat him cleanly.

Ryan Murphy won a silver medal for the United States in the men’s 200-meter backstroke and then caused some fireworks in his news conference when he questioned whether his race, won by a Russian, was drug free, given Russia’s history of doping in sports.

“I don’t know if it was 100 percent clean,” Murphy said, “and that’s because of things that have happened in the past.”

Evgeny Rylov won in an Olympic record time of 1 minute 53.27 seconds. Rylov took control of the race on the second turn, stretching his lead to a half-second at the halfway mark and finishing about half a body length ahead of Murphy, who was the defending Olympic champion in the event.

Rylov won by 0.88 of a second, but after the race Murphy dived into the fray of whether Russian athletes should be allowed to compete at the Games, given the country’s history of state-sponsored doping. Russia’s athletes are competing in Tokyo as representatives of the Russian Olympic Committee, and all who were allowed to race had to go through a rigorous clearing process before being allowed to participate.

Still, Murphy directly questioned whether his race had been free of doping. He took care not to directly accuse Rylov, who was seated four feet to his left, of cheating but referred more generally to Russia’s doping history.

Rylov chose not to address Murphy’s comments, saying only that he was a supporter of clean sports and that he had followed all the procedures that were required for him to swim at the Olympics. Murphy then clarified that he was not making a direct accusation but did not back away from his statements.

“I need to be clear,” he said. “My intention is not to make any allegations here. Congratulations to Evgeny; congratulations to Luke. They both did an incredible job. They’re both very talented swimmers. They both train real hard, and they’ve got great technique.”

The bronze medalist in the race, Luke Greenbank of Britain, took the same stance as Murphy. “It’s frustrating knowing there’s a state-sponsored doping program going on and not more being done to tackle that,” he said afterward.

The Russian Olympic Committee dismissed the comments as poor sportsmanship. “How badly our victories unnerve our colleagues,” it said in a tweet. “Here we go again — the same old song about Russian doping is played by the old music box. Someone is diligently turning the handle.”