BEIJING, China (CNN) -- Eight Americans arrested for planning or staging protests in Beijing were deported to the United States on Sunday, a U.S. Embassy spokesman said.

The U.S. Ambassador to China, Clark T. Randt Jr., had criticized the Chinese government for holding the Americans for several days.

He said it was the first time he knew of that a foreign national was detained for more than a few hours after being detained for protesting during the Olympic Games, which ended Sunday.

Six American members of the group "Free Tibet Reporters" and two Americans who unfurled a "Free Tibet" banner were put on a China Air flight to Los Angeles about 9 p.m. Sunday (1300 GMT), said Nick Snyder, a spokesman for the U.S. Embassy in Beijing.

Chinese law allows police to hold foreign nationals in jail for up to two weeks before pressing formal charges, but most other foreign protesters that China detained were held for only a few hours before authorities deported them.

The six members of "Free Tibet Reporters" were held for about four days, the embassy said, while the other two Americans were detained for about three days.

"We urge China to take positive steps to address international and domestic concerns about its record on human rights and religious freedom," Snyder said.