When Afghan Paralympian Hossain Rasouli stepped onto the Tokyo track on Tuesday morning after escaping Taliban-held Kabul, fellow long jumper Roderick Townsend didn't feel rivalry but "joy".

The American did not even know Rasouli was competing in the men's T47 long jump final until he saw 13 names on the start list rather than the usual 12, AFP reported.

Rasouli had arrived in Tokyo last Saturday, too late to compete in his favoured T47 100m event, after catching a top-secret flight from Paris one week after being evacuated from Kabul.

So instead he entered the long jump final, finishing last but symbolising for Townsend "so much about the Paralympic Games and what it means and what it stands for".

"With everything going on right now, I couldn't help but feel joy for him," said Townsend, who took silver in the event with a jump of 7.43m, AFP reported.

"We get so caught up in our personal lives, and I'm here complaining about a silver medal and we have somebody making their way across the world to be able to do something that we all love to do."

Rasouli arrived in Tokyo with Afghan team-mate Zakia Khudadadi on Saturday, after leaving their Taliban-controlled homeland a week earlier in what Games chiefs called a "major global operation".

The pair spent a week in Paris at a French sports ministry training centre following their evacuation from Kabul.

Officials initially appeared to rule out the possibility of the athletes coming to Tokyo.

But Rasouli, whose left hand was amputated after a mine explosion, finally made the country's belated first appearance at the Tokyo Games on Tuesday morning.

Emerging from the athletes' entrance with a wave to the team officials dotted around the spectator-free Olympic Stadium, he then pointed towards the Afghanistan Paralympic Committee logo on his white vest.

Olympic sprinter from Belarus, Krystsina Tsimanouskaya, decided to defect as she was being driven to a Tokyo airport because her grandmother told her that it wasn't safe to return home.

In an exclusive interview with Reuters in Warsaw, she said her family feared she would be sent to a psychiatric ward if she went back to Belarus, and that her grandmother had called her to tell her not to return.

"I am not one of those people who are scared. I am always staying for the truth. I respect myself. I respect my work."

"They were using enigmas, they used strange expressions about a net that I would get tangled in, that it would lead to inevitable consequences which would cause other people being fired and that it would be not good for you to. There were no direct threats. But I could understand it."

The 24-year-old athlete caused a furore on Sunday when she said coaches angry at her criticism had ordered her to fly home from Tokyo. After seeking protection from Japanese police, she flew on Wednesday to Poland instead of Belarus.

Poland, which has long been critical of authoritarian President Alexander Lukashenko and harbored many activists from Belarus, has granted Tsimanouskaya and her husband humanitarian visas but her grandmother remains there.

"Grandmother called me when they were already driving me to the airport," the athlete said. "Literally, I had some 10 seconds. She called me, all that she told me was: 'Please do not come back to Belarus, it's not safe."

Tsimanouskaya's saga, reminiscent of Cold War sporting defections, threatens to further isolate Lukashenko, who is under Western sanctions after a crackdown on opponents since last year, Reuters reported.

The sprinter, who had criticized negligence by her team coaches, spent two nights in Poland's embassy in Japan before flying out to Vienna and then Warsaw on Wednesday.

The Belarus National Olympic Committee (NOC) had said coaches withdrew Tsimanouskaya from the Games on doctors' advice about her emotional and psychological state. It did not immediately respond to requests for additional comment on Thursday.

The International Olympic Committee has started an investigation into Tsimanouskaya's case and said it would hear from the two Belarusian officials allegedly involved.

Tokyo Games organisers are investigating after a group of athletes were found drinking alcohol in the Olympic village this week, an incident attended by police, the CEO of Tokyo 2020 said on Sunday.

Reuters reported the athletes were caught drinking in a park in the athletes' village on Friday night, Toshiro Muto told a news conference, in contravention of COVID-19 measures at the Games.

"We are looking into the matter. We will take appropriate steps based on our findings," he said. Police were also at the scene, he said, adding it was not clear what action they took, if any, Reuters reported.

Muto did not give details of the number of athletes involved or their nationalities.

Organisers previously said athletes are permitted to drink alcohol only in their rooms and only if they are alone, as a precaution against COVID-19.

The Games are taking place in Tokyo without spectators and athletes and Olympic visitors have remained in a "bubble" with regular testing for the coronavirus.