Nearly 1,660 Afghans cleared by the U.S. government to resettle in the U.S., including family members of active duty U.S. military personnel, are having their flights canceled under President Donald Trump's order suspending U.S. refugee programs, a U.S. official and a leading refugee resettlement advocate said on Monday.

The group includes unaccompanied minors awaiting reunification with their families in the U.S. as well as Afghans at risk of Taliban retribution because they fought for the former U.S.-backed Afghan government, said Shawn VanDiver, head of the #AfghanEvac coalition of U.S. veterans and advocacy groups, and the U.S. official, who spoke on condition of anonymity.

The U.S. decision also leaves in limbo thousands of other Afghans who have been approved for resettlement as refugees in the U.S. but have not yet been assigned flights from Afghanistan or from neighboring Pakistan, they said.