The State Department has issued a Global Level 4 Health Alert, calling American citizens to return to the country immediately and discouraging outbound international travel unless travelers are prepared to remain abroad "for an indefinite period" mind the coronavirus pandemic.

The alert, announced Thursday, “advises U.S. citizens to avoid all international travel due to the global impact of COVID-19.” The Level 4 alert is the State Department’s top level, usually reserved for countries in crises such as Syria and North Korea.

In addition, the State Department advises that “U.S. citizens who live abroad should avoid all international travel. Many countries are experiencing COVID-19 outbreaks and implementing travel restrictions and mandatory quarantines, closing borders, and prohibiting non-citizens from entry with little advance notice. Airlines have cancelled many international flights and several cruise operators have suspended operations or cancelled trips.”

The move comes as the State Department begins repatriating American consulate and embassy staff back to the U.S. CNN spoke to a diplomat who said the lower levels of staffing consulates and embassies means less help is available to Americans overseas—including some people who are struggling to return home. Some members of Congress have asked the State Department to work harder on getting stranded citizens home.

As for the move to a Level 4, “Many factors were feeding into this, the diplomat said, including the wide range of medical capabilities across the globe, which determines how willing some State Department staff may be willing to stay,” CNN reported.

The State Department is also suspending the issuance of routine visas as of this week:

“In response to worldwide challenges related to the outbreak of COVID-19, the Department of State is suspending routine visa services in most countries worldwide. Embassies and consulates in these countries will cancel all routine immigrant and nonimmigrant visa appointments as of March 18, 2020. Check the website of the embassy or consulate for its current operating status. As resources allow, embassies and consulates will continue to provide urgent and emergency visa services.”

For any citizens who remain abroad, the State Department has some final words of advice: “Have a travel plan that does not rely on the U.S. Government for assistance.”