Washington has flagged new risks for Americans of Chinese descent traveling to China, and Taiwan is echoing the warning — bad news for anyone with family or business ties across the strait.

• The US updated its China travel advisory, keeping it at level two but singling out Chinese-American citizens as facing extra risk of arbitrary detention, surveillance, and exit bans.
• Beijing does not recognize dual citizenship, so former Chinese nationals who become American citizens can still be treated as Chinese and held.
• Spying investigations disproportionately target Chinese-Americans, especially those who worked for or are linked to the US government.
• Anyone entering on a Taiwan compatriot permit is treated as Chinese, and their American citizenship is ignored.
• Taiwan's Mainland Affairs Council urged government employees to avoid trips to China entirely and told ordinary travelers to think twice.

Outlook: Expect more cases of detained dual nationals and tighter travel guidance from both Washington and Taipei.