The Centers for Disease Control and Prevention is warning travelers against visiting popular destinations including France and Portugal because of "very high" levels of COVID-19.

The health agency Monday issued a "level 4" recommendation against travel to France, Portugal, Jordan, Cyprus, Andorra, Jordan, Liechtenstein and Tanzania, adding to a long list of destinations including Germany and Denmark.

The recommendation comes as the CDC continues to monitor COVID-19 risk in destinations around the globe.

If you must travel to one of the CDC's "level 4" destinations, the health agency wrote to "make sure you are fully vaccinated before travel."

The State Department issued an aligning warning against travel to France, Portugal, Jordan, Cyprus, Andorra, Jordan, Liechtenstein and Tanzania and added Fiji to it's "Do Not Travel" list because of COVID-19 "related restrictions."

The CDC assesses COVID-19 risk based on each destination's new cases and new case trajectory. The Travel Health Notice level can be raised if a large increase in COVID-19 cases is reported or a destination's case count meets or exceeds the threshold for a higher level for 14 straight days. Level 4 destinations have more than 500 new cases per 100,000 people over the past 28 days or more than 500 cases total if their population is smaller than 100,000.

Americans traveling abroad should be aware of the new U.S. travel system in place for their return. The new rules, which include tighter testing requirements for unvaccinated Americans, rolled out Nov. 8.