The US on Thursday warned against any international travel due to the coronavirus pandemic and advised citizens to come home if possible.
The State Department said the growing number of temporary entry restrictions by governments as well as airline cancellations made smooth travel impossible.
"In countries where commercial departure options remain available, US citizens who live in the United States should arrange for immediate return to the United States, unless they are prepared to remain abroad for an indefinite period," the State Department said as it upgraded its travel advisory to the highest level.
"US citizens who live abroad should avoid all international travel," it said.
The State Department also said that some US embassies had lower capacity to assist citizens due to departures of personnel over COVID-19.
The US Centers for Disease Control and Prevention (CDC) on Thursday reported 10,491 cases of coronavirus, an increase of 3,404 from its previous count, and said the death toll had risen by 53 to 150, the biggest one-day jump so far.
The US is now fast-tracking antimalarial drugs for use as a treatment against the coronavirus.

South Florida begins drive through testing for COVID-19. Source: Miami Herald/TNS/Sipa USA
The announcement follows encouraging research into chloroquine and hydroxychloroquine in France and China, but many in the wider scientific community have cautioned more work is needed to prove they really work for COVID-19.
"We're going to be able to make that drug available almost immediately, and that's where the [Food and Drug Administration] has been so great," President Donald Trump told reporters, referring to both antimalarials.
"They've gone through the approval process, it's been approved."
"They took it down from many, many months to immediate. So we're going to be able to make that drug available by prescription."
If you believe you may have contracted the virus, call your doctor, don’t visit, or contact the national Coronavirus Health Information Hotline on 1800 020 080.
If you are struggling to breathe or experiencing a medical emergency, call 000.
Additional reporting: Reuters