Sources at the State Department have told CNN that "a few" U.S. citizens or people with legal status in the U.S. are currently being kept in Chinese detention camps.

What do we know about the camps?

Although it officially denies their existence, China has a number of internment camps where it holds people it sees as a threat to the country's communist regime. Between 1 million and 2 million members of the country's Muslim Uighur minority are being held in these camps to make them comply more closely with Chinese communist dictates. However, the Chinese government says that these people are "trainees" in "vocational education" centers.

According to the State Department sources who spoke to CNN, these detainees may include some Americans. The State Department has issued a warning for any American citizens traveling to the Xinjiang region of China. China does not recognize dual citizenship, which means that it may not cooperate with the U.S. government if someone is a citizen of China and the U.S.

The U.S. Embassy in China warns American travelers that "[w]hile in China one is subject to the same laws as is a Chinese citizen. A U.S. passport does not entitle its bearer to any special privileges. One should not expect to receive preferential treatment or to expect that the same array of legal rights accorded one under the U.S. judicial system are necessarily applicable in China."

Is a US resident being detained?

On Thursday, Ambassador at Large for International Religious Freedom Sam Brownback said he had received a report about a 75-year-old legal U.S. resident with health problems who had apparently been detained in Xinjiang. He "has not been heard from since. And he's deeply concerned about whether, what his treatment is," Brownback told the media.