Olympic athletes in China have been advised to not make political comments about the country.

Expressions that are in line with Olympic spirit will be encouraged while “Any behavior or speech that is against the Olympic spirit, especially against the Chinese laws and regulations, are also subject to certain punishment,” said Yang Shu, deputy director-general of international relations for the Beijing Organizing Committee in a press conference.

On Tuesday, speakers at a seminar hosted by Human Rights Watch said athletes should not discuss China’s treatment of Uyghur Muslims, according to Reuters.

China has previously sent people to prison for expressing political views.

Yang declined to comment on what the maximum punishment could be for doing so.

Athletes have been told to not expect the International Olympic Committee to protect them if they chose to stand up for human rights.

“Chinese laws are very vague on the crimes that can be used to prosecute people’s free speech. People can be charged with picking quarrels or provoking trouble. There are all kinds of crimes that can be leveled at peaceful, critical comments. And in China the conviction rate is 99%,” said Yaqiu Wang, a researcher on China for Human Rights Watch.

U.S. Nordic skier Noah Hoffman, who competed in the 2014 and 2018 Games, expressed his disappointment in athletes not being able to speak out against human rights abuses given their large platform during the Olympics.

Hoffman said they should stay silent for their own safety but should speak out when they arrive home.