The U.S. State Department on Monday raised its travel advisory to level four, putting Japan in a category with a broad swath of nations from Latin America to Europe that Americans are urged to avoid over coronavirus concerns. The action is a fresh blow to a country struggling to convince its own public and the broader international community that it’s ready to host the Summer Olympics beginning on July 23, following their delay in 2020.

Japan’s coronavirus cases are rising as it has lagged in its vaccine rollout. Roughly 3% of the island nation’s population has been inoculated, the lowest among the 37 members of the Organization for Economic Cooperation and Development, according to Bloomberg’s vaccine tracker. That compares with more than 40% in the U.S. and in the U.K.

The latest Covid-19 wave has largely been driven by more infectious strains from abroad, adding to concerns about inviting thousands of overseas participants including athletes and officials.

Initially, 600,000 fans from abroad had been projected to attend, but organizers ruled out that possibility in March. Organizers are set to decide next month if even local spectators will be allowed to watch the competition in person. They already have reduced the number of officials and others expected to attend from overseas to about 78,000, not including athletes.

Read more: Facing Backlash, Japan Ponders a Zero-Spectator Olympics

Foreign athletes, meanwhile, have expressed safety concerns, with the U.S. track and field team canceling pre-Olympics training in the country.