The US State Department raised its advisory for all overseas travel to the highest possible level.
The Level 4: 'Do Not Travel' advisory covers all international travel and is calling on all Americans overseas to 'arrange for immediate return to the United States, unless they are prepared to remain abroad for an indefinite period.'
Flight options to get home are fast disappearing.
"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," it said.
"Airlines have cancelled many international flights and several cruise operators have suspended operations or cancelled trips. If you choose to travel internationally, your travel plans may be severely disrupted, and you may be forced to remain outside of the United States for an indefinite timeframe."
The Level 4 advisory is on an unprecedented scale.
It has been used before but only targeted at a small number of nations the US deems as risky for American travelers, such as North Korea, Syria, Iran, and Yemen.
The State Department said it is suspending normal visa services in most countries due to the pandemic which is another factor for raising the travel advisory.
In addition, new passports would only be processed 'for customers with a qualified life-or-death emergency and who need a passport for immediate international travel within 72 hours.'
The department is 'doing everything we can to protect American citizens all across the world' said secretary of state Mike Pompeo.