The Centers for Disease Control and Prevention (CDC) on Monday added Russia to its coronavirus travel warning list, classifying the country as level 3 of 4 in pandemic severity.

“Make sure you are vaccinated and up to date with your COVID-19 vaccines before traveling to Russia. If you are not up to date with COVID-19 vaccines, avoid travel to Russia,” wrote the CDC in an its update.

The CDC said that Russia has a high level of coronavirus transmission and that “anyone 2 years or older should properly wear a well-fitting mask in indoor public spaces” in the country.

The agency also updated travel warnings for the Philippines and Nepal on Monday, classifying both as high in COVID-19 transmission.

Travel to Russia is already considered precarious amid the country’s ongoing conflict with Ukraine and the detention of American WNBA player Brittney Griner and former Marine Paul Whelan.

The State Department released a travel advisory for Russia on July 22 reading “Do Not Travel and Leave Immediately.” The advisory specifically mentioned the possibility of wrongful detentions such as those of Griner and Whelan.

“Do not travel to Russia due to the unprovoked and unjustified invasion of Ukraine by Russian military forces, the potential for harassment against U.S. citizens by Russian government security officials, the singling out of U.S. citizens in Russia by Russian government security officials including for detention, the arbitrary enforcement of local law, limited flights into and out of Russia, the Embassy’s limited ability to assist U.S. citizens in Russia, COVID-19-related restrictions, and terrorism,” the advisory said.

The department also warned that American credit and debit cards no longer work in Russia amid sanctions over its invasion of Ukraine and that airlines have been changing plans due to the Russia-Ukraine conflict and it may be difficult to leave the country.