The U.S. State Department raised its travel advisory for Japan to Level 2 on its four-notch scale on Saturday because of what it termed "sustained community spread."

The number of confirmed domestic cases grew to 132 after the health ministry said on Saturday it had confirmed 27 new cases of the flu-like illness.

That is separate from the more than 600 cases from the Diamond Princess, the biggest concentration of infections outside China.

Among the new cases on Saturday was a boy under 10 years old in the northern prefecture of Hokkaido, and also a teacher in Chiba Prefecture east of Tokyo who had gone to school while she had symptoms.

Children had been thought to possibly be less vulnerable to the new virus, with far fewer reported infections in much younger people.