(Bloomberg) -- The U.S. is considering a plan to require all foreign visitors to be vaccinated for the coronavirus, according to a White House official.

The potential move comes amid a surge in Covid-19 cases causes by the highly infectious delta variant; officials expect infections to continue to rise among the unvaccinated population in the coming weeks.

Interagency working groups have been developing a plan for international travel, which they intend to roll out once borders have been reopened. The plan would include a phased approach that will mean, with a few exceptions, foreigners traveling to the U.S. would have to be fully vaccinated, the official added.

The timing of the roll-out was unclear. Reuters first reported on deliberations over the plan.

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