Krystsina Tsimanouskaya said her Olympic team officials tried to remove her from Japan, in a dispute that led to a standoff Sunday evening at Haneda Airport in Tokyo.
“I was put under pressure and they are trying to forcibly take me out of the country without my consent,” the 24-year-old runner said in a video on social media.
The IOC said it was "looking into the situation and has asked the NOC for clarification."
The Belarusian Sport Solidarity Foundation says the athlete did not board the flight and summoned Japanese police. Foreign ministry officials arrived later at the airport.
An activist group supporting Krystsina Tsimanouskaya said she believed her life was in danger in Belarus and would seek asylum with the Austrian embassy in Tokyo.
The sprinter, who is due to run in the Olympic 200-meter heats Monday, criticised Belarus team officials on her Instagram account.
She said she’d been put in the 4x400 relay despite never racing the event.
The Belarusian Sport Solidarity Foundation (BSSF) said government supporters targeted the athlete, and Tsimanouskaya contacted the group for help to avoid what she feared was a forced deportation to Minsk.
In a statement released by the BSSF, Tsimanouskaya said she was in a police station early Monday morning.
“I explained the situation to a police officer of how I was taken from the Olympic Village,” she said. “Now I am in a secure situation and am figuring out the question of where I will spend the night.
Belarus’ neighbor, Poland, where many critics of the Minsk regime have come to live, offered the athlete help.
Deputy Foreign Minister Marcin Przydacz said on Twitter that Tsimanouskaya has been offered a “humanitarian visa and is free to pursue her sporting career in Poland if she so chooses.”
The Belarus National Olympic Committee (BNOC) has been led for more than 25 years by authoritarian state president Alexander Lukashenko and his son, Viktor.
Both Lukashenkos are banned from the Tokyo Olympics by the IOC which investigated complaints from athletes that they faced reprisals and intimidation in fallout from protests since last August after the country’s disputed presidential election.
The opposition leader in Belarus, Sviatlana Tsikhanouskaya, wrote on Twitter that Tsymanouskaya "was forced by the regime to leave" Tokyo and return home.
She added: "She's afraid to come back to Minsk. No athlete should be forced this way."
The politician, who has been exiled from her home country, posted an update later on Sunday thanking the IOC for its "quick reaction" to the situation.
"She [Tsymanouskaya] has a right to international protection & to continue participation in the Olympics," she wrote.
Protests erupted in the wake of the contested result which prompted a violent crackdown by authorities in the country.
In June, Belarus diverted a flight from Ahtens to Vilnius under the guise of an alleged bomb threat. Once grounded, authorities rushed onboard to arrest dissident Belarusian journalist and opposition activist Roman Protasevich.