“We have asked for their immediate release and are continuing to follow their cases closely,” embassy spokeswoman Susan Stevenson told AFP.
Two other Americans were detained at a separate protest on Thursday near the Olympic area, along with a German national and a Briton.
The Wall Street Journal also reports:
China won the right to the host the Olympics in part by promising to improve human rights. Human-rights advocates say instead the government has staged a crackdown on dissidents, and detained or harassed Chinese applicants for special protest zones set up by the government during the Olympics.
The government has deported most of the foreigners who have managed to stage scattered, brief protest. Among the most active have been those pushing for a free Tibet. Extended detention for foreigners under such circumstances is unusual.