WASHINGTON -- U.S. officials aren't ruling out the possibility that fully vaccinated foreign visitors will need a recent negative COVID-19 test in order to cross the land border with Canada.

The latest rules for foreign air travellers, updated Monday by the White House, say fully vaccinated passengers will need to show proof of a negative test taken within three days before boarding.

The new international travel rules, which also require that foreign nationals be fully vaccinated, are scheduled to take effect Nov. 8.

Dr. Cindy Friedman, chief of the travellers' health branch of the Centers for Disease Control and Prevention, says clarity on the rules for land-border visitors is coming soon.

Friedman says Customs and Border Protection is expected to announce in the next few days whether travellers crossing the land borders will need to show proof of a negative test.

Biden administration officials say the land-border rules will likely hew closely to the same CDC guidance that produced the requirements for air travellers.

This report by The Canadian Press was first published Oct. 26, 2021.