BEIJING • There were zero new coronavirus cases in Beijing yesterday, for the first time since the emergence of a cluster in the Chinese capital in June that prompted fears of a domestic second wave.

A total of 335 people have been infected since a cluster emerged at the city's massive Xinfadi wholesale market early last month.

Beijing's health commission said yesterday it detected only one asymptomatic case the previous day, which China does not include in its confirmed cases counts.

While the Chinese authorities are still investigating the cause of the latest outbreak, the virus had been detected on chopping boards used to handle imported salmon at Xinfadi market, prompting a ban on certain imports and increased scrutiny of foreign food suppliers.

The Beijing government has tested more than 11 million people for Covid-19 since June 11 - roughly half the city's population, officials said on Monday.

However, Hong Kong reported its largest number of local coronavirus cases in almost three months, stumping local health officials and reflecting the difficulty of eradicating the pathogen.

Hong Kong found nine new local cases, government officials said at a press briefing yesterday. That was the most since April 8, according to government data.

The authorities have yet to determine how five of the patients contracted the disease.

"Over the weekend, Hong Kong's local epidemic rapidly changed," said Dr Wong Ka Hing, an official with the Department of Health. "The situation is very severe. The new local cases are quite a lot. We will increase monitoring."

The emergence of hidden transmission chains of the virus, which can be spread via asymptomatic carriers, is a setback for a city that had largely succeeded in containing the disease for months.

AGENCE FRANCE-PRESSE, BLOOMBERG