SHANGHAI, July 15 (Xinhua) -- Shanghai reported three new imported COVID-19 cases and no increase in domestically transmitted cases on Tuesday, the municipal health commission said Wednesday.

All three confirmed cases are Chinese nationals flying from overseas.

One of the imported cases departed from Mexico on July 11 and arrived at the Shanghai Pudong International Airport via Japan on July 12.

Another confirmed case left Singapore on July 10 and arrived in Shanghai on July 11. The third left the United States on July 8 and arrived in Shanghai on July 9. They showed symptoms during the isolated observation period and were confirmed as COVID-19 patients.

All the 148 close contacts with the three on the flights have been put under quarantine.

As of Tuesday, Shanghai had reported 389 confirmed imported cases and 342 locally transmitted cases.