Five Americans have been detained in Beijing following a pro-Tibetan protest in which they spelled out “Free Tibet” with blue lights near China’s national stadium, The New York Times is reporting.

The activists, members of Students of a Free Tibet, have not been in contact with their organization since their arrest on Tuesday, the Times reported.

The Beijing Olympics have witnessed several demonstrations against China, Reuters reported Wednesday. According to the Times report, Students for a Free Tibet alone has staged seven protests involving 37 people in China since the beginning of the games.

“I’d … like to emphasize that in China, activities that support Tibet independence will be strongly condemned by the Chinese people and will not be welcomed,” Qin Gang, a Chinese foreign ministry spokesman told Reuters Wednesday.

Human Rights in China, a New York-based activist group told Reuters that 24 protesters had been detained or put under watch before the Olympics opened.

China has reportedly rejected all of the dozens of applications to protest in the country, Reuters reported.

Click here to read The New York Times report.