(CNN) — Travelers entering the United States will face new protocols as cases of novel coronavirus grow around the world.

The US is expanding travel restrictions from Iran and heightening a travel advisory for certain regions of South Korea and Italy, Vice President Mike Pence said Saturday. Meantime, President Trump in a tweet on Sunday announced new screening procedures for people traveling from "high-risk countries."

New screening methods

There was already a ban on travel related to Iran, but the administration said Saturday that it is being expanded "to include any foreign national who has visited Iran within the last 14 days." As of Monday morning, there have been 978 cases of coronavirus in Iran and 54 deaths.

The US is also increasing the travel advisory for Italy and South Korea to Level 4 -- the highest level -- advising Americans not to travel to specific regions in those countries hit hardest by the virus, Pence announced through the State Department.

"Additionally we are currently working on exit screening from South Korea, Italy , and other European Nations as needed," Katie Miller, a spokeswoman for Pence, told CNN Sunday when asked to clarify what Trump meant by "high risk."

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Health and Human Services Secretary Alex Azar said the goal is to lower the travel to and from the most impacted areas in an attempt to control the spread of the virus.

Screening is already in place for those traveling from China. Anyone who has been in China within the last 14 days requires screening.

Trump on Saturday warned Americans that although more cases are "likely," most healthy people who contract the illness will recover and the risk to the average American remains low. And Pence told CNN's Jake Tapper on "State of the Union" that while the administration knows there will be more cases and that it's possible Americans could die from the disease, "the American people should know the risk for the average American remains low."

Additional restrictive measures were announced in January and are scheduled to take effect starting at 5 p.m. ET on Monday. Those include that US citizens and permanent residents returning to the United States who have traveled to Iran within the previous 14 days must enter trough an approved airport. Foreign nationals who have traveled to Iran within the last 14 days will be denied permission to travel to the US.

Airlines suspend some operations

In response to growing concerns over the spread of the virus through international travel and dwindling demand for international flights between certain locations, some airlines have suspended operations to certain airports.

American Airlines announced Saturday that it was suspending operations to and from Milan, Italy, from New York's JFK Airport and Miami International Airport. The suspension was a result of a reduction in demand, an alert from the airline said.

Change fees have been waived for anyone who purchases travel between March 1 and March 16, the airline announced Sunday.

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Delta Air Lines has also temporarily suspended daily flights between JFK and Milan's Malpensa Airport. That suspension will be effective March 2 on east bound flights and March 3 on west bound flights. Service will resume starting on May 1 and May 2, a statement from the airline said.

Delta announced reductions to service between the US and Seoul, South Korea, last week.

Flights between the US and Shanghai and Beijing also remain suspended until April 30 following travel restrictions from US Health and Human Services.

United Airlines has suspended operations between the US and Beijing, Chengdu, Hong Kong and Shanghai until April 30 due to concerns over coronavirus, a notice from the airline said.