The U.S. has implemented restrictions related to the Ebola outbreak in the Democratic Republic of Congo ​which prevent American citizens and nationals who have been in ‌the African country within a 21-day period from entering the United States via commercial aviation, the State Department said on Wednesday.

Here are some details:

Reuters first ​reported this week that President Donald Trump's administration was blocking ​American citizens in Congo from traveling to the U.S. ⁠on commercial flights.

"Travelers who have been in the DRC within 21 ​days of their flight will not be allowed to board flights ​with U.S. destinations," the website of the U.S. embassy in the country said.

"All U.S. citizens and U.S. nationals who have been in the DRC should plan ​to remain outside the DRC for 21 days before entering ​the United States."

The new restrictions come amid an Ebola outbreak which has spread to ‌multiple ⁠provinces within Congo.

Official Congolese data showed late on Sunday that the number of confirmed Ebola cases across the country had risen to 1,926, including 702 deaths.

Dr. Daniel Jernigan, a former senior U.S. Centers ​for Disease Control ​and Prevention ⁠official who led the U.S. response during the 2014-2015 Ebola outbreak in West Africa, said this week that ​using the "do-not-board" policy to prevent U.S. citizens from returning ​home ⁠when they have little risk of Ebola infection is unprecedented.

"This change in policy risks shifting medical and public-health responsibility to third countries, it ⁠may encourage ​travelers to conceal itineraries or exposures, ​and it will make recruitment of American outbreak responders more difficult," Jernigan said.

-Reuters