SHANGHAI  - China reported on Friday 64 new coronavirus cases in the mainland for July 29, compared with 49 cases a day earlier, the health authority said.

The National Health Commission said in a statement 21 of the new infections were local cases, compared with 24 the previous day. There were no new deaths.

A majority of the local cases were reported in Jiangsu province, the authority said.

The province's capital city of Nanjing is currently facing an outbreak of the delta variant that surfaced earlier this month.

The official Xinhua news agency reported that the source of the outbreak was inadequately protected airport staff who were cleaning planes after international flights.

Authorities have since conducted mass testing in the city, and closed the airport on Tuesday.

Two cases of the virus were also reported in Hunan province. One case was reported in Beijing.

The new patients in Hunan were reported after symptomless carriers outside the province were found to have attended a live performance at a theatre in the Zhangjiajie city on July 22. Local authorities deemed all spectators in the theatre during 18:00-19:00 July 22 as high virus risk.

Over 2,000 people attended performances on July 22 and guests were seated next to each other, a health publication run by state media the People's Daily said in an report on Wednesday.

China also reported 25 new asymptomatic patients, compared with 14 a day earlier.

As of July 29, mainland China had a total of 92,875 confirmed coronavirus cases, it said.

China's death toll from the coronavirus remained unchanged at 4,636.

(Reporting by Josh Horwitz and Wang Jing; Editing by Raju Gopalakrishnan and Michael Perry) ((Josh.Horwitz@thomsonreuters.com; +86 21 20830007;))