"Should I start with hello, goodbye, or condolences?" Alizadeh wrote in an emotional post that addressed her love of her homeland but anger with its regime. Alizadeh said the government took credit for her athletic achievement while at the same time humiliating her for her efforts, recalling one instance in which an official told her, "It is not virtuous for a woman to stretch her legs!"
She described how Iranian officials attributed her success to their management practices, including making her compete in an Islamic veil, which is obligatory for women under Iranian law.
"Whatever they said, I wore. Every sentence they ordered, I repeated," she wrote, adding, "My troubled spirit does not fit into your dirty economic channels and tight political lobbies"
"I have no other wish except for taekwondo, security and a happy and healthy life," she continued.
"I accept the pain and hardship of homesickness because I didn't want to be part of hypocrisy, lies, injustice and flattery. This decision is even harder to win than the Olympic gold, but I remain the daughter of Iran wherever I am."
Alizadeh did not disclose to where she had defected, mentioning only that "no one has invited me to Europe." Radio Free Europe cited her past remarks, indicating she may have gone to the Netherlands.
Some Iranian officials appeared to sidestep news that Alizadeh's defection was driven in part by clashes with the government, while others demanded answers.
Mahin Farhadizadeh, a deputy Iranian sports minister, suggested that the young athlete was bowing out of competition because of educational commitments, telling the semiofficial Iranian Students' News Agency, "I have not read Kimia's post, but as far as I know she always wanted to continue her studies in physiotherapy," according to Reuters.
Abdolkarim Hosseinzadeh, a member of parliament, accused "incompetent officials" of allowing Iran's "human capital to flee" the country, Agence France-Press reports.
Alizadeh's move drew praise from State Department spokeswoman Morgan Ortagus, who commended the Olympian for "reject(ing) the regime's oppression of women."
"She has defected for a life of security, happiness, and freedom. #Iran will continue to lose more strong women unless it learns to empower and support them," Ortagus said on Twitter late Saturday.
It's unclear whether Alizadeh will attempt to compete in this summer's Olympic Games in Tokyo under a different country's flag. The International Olympic Committee created the first Refugee Olympic Team during the 2016 Summer Games and said it would support a team in 2020, as well, though the criteria for which athletes may qualify as refugees has not been released.
After Alizadeh 2016 Olympic victory in Brazil over Sweden's Nikita Glasnovic, she kissed the mat and signaled that she would be back to compete for gold.
"I am so happy for Iranian girls because it is the first medal, and I hope at the next Olympics we will get a gold," she told reporters at the time. "I wish I had made history with a gold medal. I thank God that I made history with my bronze to pave the way for other Iranian women."