City agencies in Guangzhou stepped up efforts to contain coronavirus as China's Guangdong Province registered seven local transmissions of COVID-19 and three asymptomatic cases, health officials said Sunday.

The southern China city of Guangzhou's since May 21 reached 80 in the wake of a resurgent outbreak.

Overall, China reported 30 new COVID-19 infections in the mainland as of Saturday - up from 24 a day earlier, according to the country's health ministry Sunday.

Seven imported cases were reported Saturday. They entered Guangdong from Bangladesh, Cambodia, Canada, France, India and Cameroon, Xinhua News Agency News said. The imported cases were either confirmed or asymptomatic.

The latest resurgence in the southern manufacturing hub of Guangdong began last month, with most infections reported in cities of Foshan, Shenzhen and Guangzhou.

The outbreak of new infections has seen Guangzhou authorities enforce lockdowns in certain neighborhoods.

Shenzhen city's airport has ordered residents of Guangzhou or nearby Foshan to provide a negative COVID-19 test result before they can board planes.

According to Chen Bin, deputy chief of the Guangzhou Municipal Health Commission, mass testing of residents involving an expanded nucleic acid test is being conducted in 11 districts in Guangzhou.

China has 91,248 confirmed cases of COVID-19. Deaths remained unchanged at 4,636.

There are 173 million cases of COVID-19 worldwide with 3.72 million deaths, according to the World Health Organization.