A U.S. Customs and Border Protection officer's patch is seen in 2015 in Miami, Florida.
CNN  — 

A Canadian citizen was turned away at the northern border as a part of President Donald Trump’s temporary ban on people who have visited China before their arrival in the United States, acting Homeland Security Deputy Secretary Ken Cuccinelli said Monday.

In the wake of Trump’s proclamation, the US has started denying entry to foreign nationals who visited China in the 14 days prior to their arrival to the US. It’s not clear whether anyone else has been turned back as part of the restrictions that began at 5 p.m. ET Sunday.

“We’re just beginning, today, to see results of implementation,” said Cuccinelli, who serves on the President’s coronavirus task force.

Airlines are responsible for stopping passengers who will be denied entry into the US before they get on planes, and DHS worked with the airlines throughout the weekend and collected feedback to make it “more operationally feasible for them,” Cuccinelli said. “We recognize these are burdens on the airlines, as they are on other people as well. But we want to make it work as effectively as we can.”

The President, Cuccinelli said, based his decision on task force advice to implement certain measures to restrict travel of non-Americans who are most likely to have come in contact with coronavirus.

“The President made very clear his top priority is the safety of the American people, but that doesn’t mean a complete shutdown,” he said.

As a practical matter, planes in the air at 5 p.m. ET were treated under pre-5 p.m. ET rules, Cuccinelli said, adding that they “didn’t want to be rerouting planes” and they “wanted that all to work smoothly and above all safely without breaking the system.”

Two key determinations

US citizens and others who are allowed to travel to the US from China are being funneled to 11 airports where US authorities will conduct extra screening and transfer people for quarantine if needed.

All flights from China will go to those airports, and passengers who have been to China in the past 14 days and weren’t already traveling to one of those airports will be required to rebook their flights.

The “vast majority” of flights coming from China already arrive at those airports, Cuccinelli said.

DHS has the statutory authority to limit the locations where all flights entering the US from abroad may land. And the Transportation Security Administration, under DHS, has required air carriers to enforce the President’s proclamation that limits who is allowed to board commercial flights headed for the US.

When passengers arrive at the 11 airports, Customs and Border Protection officers make two key determinations: whether a traveler is admissible to the US and if someone needs extra screening or quarantine.

If Customs and Border Protection determines extra screening is needed, travelers are sent for a secondary screening. By the end of the week, Cuccinelli said, he expects medical professionals at the airport secondary screening to be entirely staffed from DHS contracts. Coast Guard personnel are also doing the work at some airports.

Cuccinelli said the “very small number of people who have either traveled to Hubei province or show symptoms” will go to a third screening. At that point, the Centers for Disease Control and Prevention would get involved to connect people with local authorities and possible quarantine.

“These are going to be extremely small numbers,” he said. “We’re just seeing fewer and fewer travelers from Hubei.”

At sea, the Coast Guard is responsible for enforcing the travel restrictions, and it held a ship offshore in Puget Sound until passengers had exceeded the 14-day requirement and did not show symptoms.