The United States on Saturday warned citizens of "heightened risk of arbitrary detention" in China as tensions between Beijing and Washington soared over issues including Hong Kong, Xinjiang and Tibet.

US citizens in China "may be subjected to prolonged interrogations and extended detention for reasons related to 'state security'", the State Department warned in a security alert. The State Department said Chinese authorities may also impose exit bans as part of "arbitrary enforcement of local laws for purposes other than maintaining law and order".

Beijing and Washington have traded barbs and sanctions on a slew of issues in recent months, including the coronavirus pandemic and Chinese policies in the far west regions of Tibet and Xinjiang, with Chinese authorities threatening retaliation this week for US sanctions on Chinese officials.

A controversial security law pushed on Hong Kong by China's central government in June has also caused international concern over the wording of the legislation, which bans subversive acts and speech against the Chinese government made anywhere in the world.

Australia and Canada have also issued travel warnings over fears of arbitrary detention by Beijing. Last year China arrested Australian-Chinese writer Yang Hengjun, who was indicted earlier this year for espionage. China has also arrested two Canadians after Canada detained a high-profile executive of Chinese telecom giant Huawei in late 2018.