"Exercise increased caution in China due to arbitrary enforcement of local laws as well as special restrictions on dual US-Chinese nationals," the advisory said. "Chinese authorities have asserted broad authority to prohibit US citizens from leaving China by using 'exit bans,' sometimes keeping US citizens in China for years."
READ MORE: Growth of China-US Ties 'Indispensable' For Success, Chinese Envoy to US Says
The warning comes after Chinese authorities arrested two Canadian citizens in recent weeks on suspicion of threatening national security.
China's actions followed the December 1 arrest of Huawei Chief Financial Officer Meng Wanzhou, who is also the daughter of the company's founder, in Canada on suspicion of failing to comply with US sanctions against Iran.
