The U.S. is developing a plan to require foreign travelers to be fully vaccinated before entering the country, Reuters reports, citing a White House official. The measure would be the catalyst for the U.S. lifting its travel restrictions for other countries, which have been in place since the start of the COVID-19 pandemic. The Biden administration is currently working with interagency groups to flesh out plans for when to implement the rule, but it is not expected to take place in the immediate future due to the rise in cases caused by the Delta variant. The administration has also spoken to airlines on how such a policy would be enforced, including what proofs of vaccination would be permitted. The rule would be implemented over time, a White House official said, with “limited exceptions.” The news comes after reports last week said Biden was considering implementing such requirements, but no decision had been made then.