Here are some of the other nations that have tightened access to outsiders or placed other restrictions in response to the coronavirus pandemic:

China

Nearly 81,000 cases of COVID-19 have been confirmed in China and more than 3,000 deaths, more than any other nation has experienced.

Notwithstanding a tweet on Thursday from Chinese Foreign Ministry spokesperson Lijian Zhao suggesting that "it might be US army who brought the epidemic to Wuhan," no new restrictions bar Americans from traveling to China. The U.S. State Department website reminds potential travelers that they may be prohibited by Chinese authorities from entering or exiting parts of Hubei province. Its biggest city is Wuhan, the epicenter and suspected origin of the coronavirus outbreak.

"In Hubei province, the United States does not have any further evacuation flights departing Wuhan International Airport," the State Department notes. "American citizens currently in travel restricted areas in Hubei province and other areas in China should shelter-in-place, limit contact with others, and consider stocking up on food and other supplies to limit movement outside the home."

South Korea

With more than 7,800 confirmed coronavirus cases and deaths, South Korea has suspended visa-free entry to Chinese nationals and others traveling from China. It has done likewise for Japanese nationals in apparent retaliation for similar measures that Tokyo imposed this week on travelers from South Korea. The two nations have frequently clashed over the legacy of Japan's 35-year occupation of the Korean peninsula that ended in 1945.

Japan

There have been at least 639 known cases of COVID-19 and 16 deaths in Japan. A travel ban was already in place for those Chinese citizens holding passports from highly infected areas, such as Hubei and Zheijang provinces. Similar restrictions were placed on travelers from areas near Daegu, the South Korean city at the center of that nation's coronavirus epidemic, and on travelers from Iran. People from northern Italy were added to the banned travelers list March 11.

Singapore

With 178 coronavirus cases reported but no deaths, Singapore has imposed extensive travel restrictions for outsiders. According to the U.S. Embassy in Singapore, as of March 4 anyone who is not a citizen or resident of Singapore and who has traveled within 14 days to Iran, South Korea or northern Italy would not be allowed to enter or transit through Singapore. That follows a similar ban placed Feb. 1 on travelers from China.

Spain

On March 11 Spain, with at least 2,277 confirmed coronavirus cases and 5 deaths, announced the suspension of all direct flights between Spain and Italy.

France

France, with 2,284 confirmed cases and 48 deaths, has imposed no travel restrictions. But Air France has canceled flights to and from China until the end of March, as well as flights to Italy from March 14 to April 3.

Italy

While the State Department recommends deferring all nonessential travel to Italy, Prime Minister Giuseppe Conte declared March 9 restricting movement for all Italian residents has not amounted to a travel ban for outsiders.

"While direct flights between Chinese points-of-origin and Italian destinations have been temporarily postponed," the State Department notes, "there are no specific restrictions for entry of anyone based solely on their nationality."

Italy has had at least 12,462 confirmed cases of coronavirus infection and 827 deaths, a fatality toll that is second only to China's.