US warns Americans about exit bans and 'unjust' detention in popular destination

Americans who may be planning a trip to China are urged to take extra precautions, as U.S. officials to "keep a low profile" while visiting the country.

The State Department recently updated its Level 2 "Exercise Increased Caution" advisory for mainland China, warning Americans about the arbitrary enforcement of local laws, exit bans and "the risk of unjust arrest or detention."

U.S. citizens could be questioned or detained without being told what crime they are accused of — and without being given access to U.S. consular services, according to the advisory.

"U.S. citizens in China may also face interrogations and detention without fair and transparent treatment under the law," the State Department warns.

The advisory notes that business people, academics and journalists are among those who have faced questioning, detention or expulsion for alleged violations of China's national security laws.

"U.S. citizens might only become aware of an exit ban when they attempt to depart China," the advisory states.

The State Department said the restrictions have been used to pressure people to participate in investigations, resolve civil disputes and compel relatives or associates to return to China.

In some cases, exit bans have remained in place for years, preventing U.S. citizens from leaving the country even to receive according to the advisory.

Officials are also warning Americans to be careful about what they say and share electronically while traveling.

"Assume that China's security services can read your emails, texts, and if you send them to or from China," the advisory states.

The State Department warns that Americans could be detained or deported for private electronic messages , Hong Kong, Macau or the Chinese Communist Party. 

Authorities have detained people over messages sent while they were outside China, according to the advisory.

For Americans who decide to travel to mainland China, officials recommend avoiding demonstrations and being .

Travelers are also advised to avoid sharing opinions either publicly or privately that Chinese authorities could consider embarrassing or negative and to avoid or police without permission.

"Keep a low profile," the State Department advises.

The updated advisory also includes separate guidance for and Macau.

Americans are advised to exercise increased caution in Hong Kong due to the arbitrary enforcement of local laws. 

Macau carries a higher Level 3 "Reconsider Travel" advisory due to similar concerns and the U.S. government's limited ability to provide emergency consular services there.

Fox News Digital reached out to the State Department for comment and further information.