BRUSSELS — The European Union took a crucial step on Monday toward reopening its borders to vaccinated travelers after the bloc’s executive released a plan for allowing journeys to resume after more than a year of stringent coronavirus restrictions.

The European Commission, the executive branch of the European Union, proposed that the 27 member countries reopen their borders to all travelers who have been fully vaccinated with shots approved by the bloc’s medicine regulator or by the World Health Organization. The commission also outlined other, looser, pandemic-related conditions that should permit people to travel.