Today the Trump administration said it will bar entry to the US of foreign nationals who’ve recently been to China. The temporary measure, which will throw many a travel plan into disarray, comes in response to a rapidly spreading coronavirus outbreak that has sickened thousands of people around the world and killed hundreds in China, where it originated in the central city of Wuhan.

The restriction will go into effect Sunday (Feb. 2) at 5pm, applying to any foreign national who has been in China in the last 14 days, said Alex Azar, secretary of Health and Human Services Secretary, at a White House media briefing.

An exception will be made for immediate family of US citizens and permanent residents, he said, but a mandatory 14-day quarantine awaits US citizens who’ve traveled to China’s Hubei Province within the last two weeks. Before this a federal quarantine order hadn’t been issued since the 1960s.

Azar added that Americans returning from other parts of China will face screening at select ports of entry and be asked to perform a 14-day “self-isolation” period at home, with local health officials monitoring their condition.

Azar also said the US was declaring a public health emergency over the virus.

All flights from China will be diverted to seven airports: San Francisco, Seattle, Los Angeles, Honolulu, Atlanta, O’Hare in Chicago, and John F. Kennedy in New York.

Today the US State Department also warned Americans to avoid all travel to China due to the outbreak.