The Biden administration is developing a plan to require nearly all foreign visitors to the United States to be fully vaccinated against COVID-19 as part of eventually lifting travel restrictions that bar much of the world from entering the United States, a White House official told Reuters on Wednesday.

The White House is not ready to immediately lift travel restrictions because of the rising COVID-19 case load, the official said.

The Biden administration has interagency working groups working “in order to have a new system ready for when we can reopen travel,” the official said, adding it includes “a phased approach that over time will mean, with limited exceptions, that foreign nationals traveling to the United States (from all countries) need to be fully vaccinated.”