Hong Kong on Saturday reported 27,647 new coronavirus cases while Shanghai closed schools and parks and authorities in Beijing suspended access to a residential area and told the public not to leave the capital after new infections were found.

Hong Kong leader Carrie Lam warned the territory's wave of infections may not have peaked despite stringent controls on travel and business.

“At this moment, we could not comfortably say that we have passed the peak,” Lam said at a news conference. “We’d rather take a very cautious stance.”

On the mainland, the government reported 588 new confirmed cases and no death in the 24 hours through midnight Friday. Its numbers are low compared with some countries, but authorities say they are ready to lock down communities if one case is found.

The Shanghai city government, where 22 new cases were reported Saturday, announced schools would switch back to teaching online.

Public attractions including the Oriental Pearl TV tower began requiring visitors to show negative results from virus tests, according to news reports.

In Beijing, where five new cases were reported, part of the Yosemite housing complex in the northeastern district of Shunyi was closed after an infection was found there. Residents were ordered to undergo testing.

The government said the infected person found there was a close contact of an earlier case in the capital.

“Please do not leave Beijing unless necessary,” a spokesman for the capital’s Communist Party committee, Xu Hejian, was cited by state TV as saying.

The new cases included 134 in Jilin province in the northeast, where the industrial city of Changchun with a population of 9 million was put on lockdown Friday.

Changchun and the Jilin provincial capital, also called Jilin, are “still at the peak of community transmission,” the province’s party secretary, JIng Junhai, said in a statement.

On Saturday, the government announced Mayor Wang Lu of Jilin was replaced but gave no reason.

Yucheng in Shandong province also was on lockdown under China’s “zero tolerance” strategy, which aims to find and isolate every case.