SHANGHAI, July 7 (Reuters) - China reported 57 new COVID-19 cases in the mainland for July 6, up from 23 cases a day earlier, the national health authority said on Wednesday.

It was the highest daily tally of infections since Jan. 30.

Fifteen of the new cases were local infections, the National Health Commission said in a statement. All 15 cases were located in the Yunnan province, in the city of Ruili which borders Myanmar.

The number of new asymptomatic cases, which China does not classify as confirmed cases, rose to 41 from 25 cases a day earlier.

The total number of confirmed COVID-19 cases in mainland China now stands at 91,949. The death toll remains unchanged at 4,636. (Reporting by Andrew Galbraith and Winni Zhou; Editing by Himani Sarkar)