As European countries prepare to reopen their borders to international travel, officials at the European Commission have been working with member states on advising which visitors might be considered safe to visit from July 1.

While multiple sources told CNN they had not seen lists of specific countries, officials said they were working on criteria that would be used to draw up guidance. Discussions were ongoing, the sources said.

The guidance will be based on how countries of origin are managing the coronavirus pandemic, at a time when some parts of the world are seeing cases surge. "The criteria will be focused on circulation of the virus," said one EU diplomat, adding that Brussels is looking to keep out travelers from countries "where the virus is circulating most actively."