People walk through a sparse international departure terminal at John F. Kennedy Airport (JFK) as concern over the coronavirus grows on March 7, 2020 in New York City.

U.S. airline stocks plunged Thursday after President Donald Trump announced sweeping travel restrictions, including an unprecedented 30-day ban on foreigners arriving from most of Europe, a measure he said was necessary to stop new cases of coronavirus "from entering our shores."

Trump in a televised address called the new coronavirus "foreign" and attacked Europe for not taking the same actions to control the disease that he had.

"As a result" of Europe's inaction, Trump said, "a large number of clusters" of coronavirus "were seeded by travelers from Europe."

Trump mischaracterized the restrictions in his national address, sowing confusion among airline employees, travelers and fears among investors about the additional financial hit the ban poses to carriers.

American Airlines shares were down 15% in premarket trading, United fell 15% and Delta dropped 13%.

Savanthi Syth, a Raymond James airline analyst called Trump's travel restriction "a baffling move that appears to be based on political theater rather than facts."

The director of the National Institute of Allergy and Infectious Diseases, Anthony Fauci, last month said travel restrictions are "irrelevant" if the coronavirus becomes a pandemic, which is how the World Health Organization characterized it on Wednesday. "When you have multiple countries involved, it's very difficult to do; in fact, it's almost impossible," he said.

Airlines were already scrambling to cut costs by reducing flights, offering employees unpaid, voluntary leave and freezing hiring, as the virus spreads and new travel restrictions are implemented, sapping demand.

Trump in a televised address called the new coronavirus "foreign" and attacked Europe for not taking the same actions to control the disease that he had.

"As a result" of Europe's inaction, Trump said, "a large number of clusters" of coronavirus "were seeded by travelers from Europe."

Trump's order bars most foreigners who have been in Europe in the last two weeks from entering the U.S. for 30 days. While it stopped short of a flight ban, the measure would likely further diminish demand for trans-Atlantic travel, prompting more flight cuts. It leaves it up to airlines to cut flights, similar to the entry restrictions on U.S.-bound travelers who were in China that the administration announced. The U.K. is exempt from the new order.

"This action will hit U.S. airlines, their employees, travelers and the shipping public extremely hard," Nicholas Calio, president of Airlines for America, a trade group that represents airlines including American, Delta, United and delivery giants FedEx and UPS, said in a statement. "However, we respect the need to take this unprecedented action and appreciate the Administration's commitment to facilitate travel and trade."

The State Department has also issued a Level 3 warning that recommends U.S. citizens to reconsider all travel abroad, "even countries, jurisdictions, or areas where cases have not been reported may restrict travel without notice."