People who were in the Democratic Republic of Congo, or neighbouring Uganda or South Sudan, within the past 21 days must now enter the US via Washington Dulles International Airport which serves the nation’s capital, the Centers for Disease Control and Prevention (CDC) said.

US customs and border protection issued the rule that went into effect for flights departing after 11.59pm (0359 GMT) on May 20.

The CDC said that going forward, anyone scheduled to travel to US destinations from the impacted countries will be contacted by their airline to rebook to Dulles airport, located in suburban Virginia.

The state’s department of health said in a statement they are in “active communication” with federal partners and that the “risk to the general public remains very low.”

At Dulles, the redirected passengers will undergo “enhanced” screening that will include a questionnaire on travel history.

Travellers will be observed for signs of illness and receive temperature checks, and will also provide contact tracing information.

If they have no symptoms, passengers will be able to continue to their final destinations and will be provided instruction on symptom monitoring, the CDC said.

The screening regulation applies to US citizens, US nationals and lawful permanent residents.

Washington had already announced entry restrictions on non-US passport holders if they had travelled to DRC, Uganda or South Sudan within the past 21 days.

The World Health Organization has declared the latest deadly outbreak of the highly contagious hemorrhagic fever an international emergency.

While the WHO believes the risk from the Ebola outbreak is high both in the DRC and the wider central African region, it considers the risk of a worldwide pandemic to be “low.”