The State Department on Thursday advised Americans to avoid all international travel, raising its global health warning to the highest level of 4 amid the worldwide spread of the new coronavirus.
The State Department also said U.S. citizens who are now in other countries should arrange for "immediate return" to the United States unless they are prepared to remain abroad for an indefinite period.
With many countries implementing travel restrictions and mandatory quarantines and airlines canceling flights, travel plans could be "severely disrupted" and individuals "may be forced to remain outside of the United States for an indefinite timeframe," the department said.
The Global Health Advisory had been at level 3, which calls on U.S. citizens to "reconsider travel." But travel advisories for China, where the virus originated, and the worst affected regions of Italy and South Korea were already at level 4. Japan had been at level 2, which calls for "increased caution."
The move comes as the United States sees a surge in confirmed infections on the back of enhanced testing capabilities, with the figure surpassing 10,000, on Thursday, with a total of 150 deaths, according to data from the Centers for Disease Control and Prevention.
In an effort to keep the virus at bay, the administration of U.S. President Donald Trump has already barred the entry of foreign travelers coming from mainland China as well as from Iran and many European countries.
The "Do not travel" advisory will come as a blow to Japan as it prepares to host the Tokyo Olympics from late July. It enjoys close business ties and active exchanges with the United States, with over 1.7 million Americans visiting Japan in 2019.
Trump said Thursday that G-7 leaders including Japanese Prime Minister Shinzo Abe had discussed the possible postponement of the Olympics during Monday's emergency videoconference to coordinate steps against the virus outbreak.
His comments came as doubts continued to mount about whether the Olympics could be held as scheduled. Qualifying events are being canceled around the world and athletes are voicing concerns that moving ahead with the games would put their health at risk.
"We did discuss it," Trump told a press conference. "We don't know what his (Abe's) decision is, but we would live with his decision. It's a tough situation...Japan has done an incredible job on building the venues," he said.
The U.S. president had initially been optimistic about Tokyo hosting the Olympics as planned even as Japan was seeing infection cases on the rise, saying in late February that he hoped the situation would be "fine."
But last week, Trump suggested postponing the Tokyo Olympics for a year, saying that the move would be better than seeing "empty stadiums all over the place."
After the videoconference involving the leaders of Britain, Canada, France, Germany, Italy, Japan and the United States as well as the European Union, Abe told reporters that he secured support to hold the Tokyo Olympics and Paralympics in their "complete form" to prove that "humankind can overcome" the virus.
But he did not indicate whether the leaders discussed any possible changes to the scheduling of the games. The Olympics are scheduled to run from July 24 to Aug. 9, and the Paralympics from Aug. 25 to Sept. 6.