WASHINGTON (REUTERS) - The US Department of Homeland Security (DHS) issued rules on Sunday (Feb 2) to implement new restrictions on Americans who have recently visited China to address the threat of the coronavirus.

Airline officials said Sunday the new rules will mean they must now ask all US-bound passengers if they have visited mainland China. Airlines may need to scrutinise passports of travellers, and warned the new rules could require passengers to arrive even earlier for US-bound flights.

American Airlines Inc said Sunday it encouraged US-bound passengers "to arrive at the airport three hours early as we expect this additional screening will lengthen the normal check-in process."

The United States said Friday that for flights departing after 5pm EST Sunday, it will bar entry to nearly all foreign visitors who have been in China within the last two weeks.

The Trump administration is limiting flights from China and for Americans who have visited China within the last 14 days to seven major US airports for enhanced screening: New York's JFK, Chicago's O'Hare, San Francisco, Seattle-Tacoma, Honolulu, Los Angeles and Atlanta.

The new rules do not impact cargo-only flights, DHS said.

American Airlines temporarily halted all flights to mainland China on Friday, while Delta Air Lines said Saturday its last flight from China would arrive Sunday before resuming flights in May. United Airlines is scheduled to continue flights through Wednesday before halting flights through March 27.

Airlines must ensure foreign visitors arriving in the United States have not visited China within the last two weeks and Americans who travelled within the last 14 days to China are flying to one of the seven designated airports.

Airlines said they are working to ease the burden on gate agents by also including questions about China travel online and at check-in lobbies, and adding new signs.

A spokeswoman for a group representing US airlines said Sunday "carriers will continue to comply with all government rules and regulations."

DHS warned that "travellers without a nexus to China may also be routed through one of these seven airports if it is discovered mid-flight that someone else on their flight has been in China in the last 14 days."

Americans who have been in Hubei, China province within 14 days of their return will be subject to up to 14 days of mandatory quarantine.

US citizens who have been in other areas of mainland China within the last 14 days "will undergo proactive entry health screening and up to 14 days of self-quarantine," DHS said.

For Americans who recently travelled to China - but outside Hubei - if they show no symptoms after a screening "they will be re-booked to their destination and asked to 'self-quarantine' at their homes." DHS said Sunday none of restrictions impact flights or visitors from Hong Kong or Macau.