Measures to tighten frozen food oversight

"It is more likely to have been imported via contaminated seafood from abroad," Wu said.

China reported 102 new locally transmitted cases of COVID-19 infections on Wednesday. Ninety-six were reported in the Xinjiang Uygur autonomous region, five in Dalian, and one in Beijing, according to National Health Commission.

Based on recent data, China had 400 locally transmitted cases from July 23 to 29.

But the latest outbreak in Dalian has been basically contained, and no further large-scale spread is expected, Wu said.

"Because of the timely quarantine, there is no great risk of transmission," he said.

Since Sunday, Dalian has been arranging free coronavirus tests for all of its residents. As of Wednesday, about 4.1 million samples had been collected, said Zhao Lian from the city's health commission.

In Urumqi, capital of Xinjiang, the city government highlighted the strengthened management on people leaving the city to contain the spread of infections, like the need for 14-day quarantines in the city and negative nucleic acid test results, said the city's Deputy Mayor Song Yajun on Thursday.

In addition, the city government decided to increase the supply of meat and vegetables for the city's Muslims, who are preparing to celebrate the Eid-al-Adha holiday on Friday, Song said.

"The butchering in Urumqi will be accelerated during the holiday, and the city will provide abundant foods, including more fresh meat and vegetables on the market with fair prices," he said.

According to Song, the city's government has been guiding to stabilize the market prices of daily needs since July 24, and nearly 20 million yuan ($2.8 million) of financial subsidies have been put in place.