A dance training center in the Futian district of Shenzhen, Guangdong province, is under legislative investigation of possible involvement in a cluster of COVID-19 infections, according to local authorities.

The Huaxing Dance Art Center, located on the fourth floor of the Dongyuan Building, had reported 28 positive cases as of 6 pm on Wednesday, the district's headquarters for epidemic prevention and control said.

Some of people who visited the dance center had been to other districts in Shenzhen or certain places outside the city, the headquarters said. "There are still risks of further spread," it added.

The district has carried out a series of measures to cut off transmission chains, including quarantines and static management. A thorough check for infections is ongoing in confined spaces, including karaoke rooms, dance classrooms and gyms. People who work in the service industry and are at greater risk of infection will receive more testing.

Shenzhen reported 62 positive cases on Wednesday, with 26 of them connected with the dance center, the health authorities said.