People line up for virus testing in Anyang

A third Chinese city has locked down its residents because of a COVID-19 outbreak, raising the number confined to their homes to about 20 million people.

It wasn't clear how long the lockdown of Anyang city, home to 5.5 million, would last. Authorities said it was being done to facilitate mass testing but did not indicate if it would end when the testing is completed. Another 13 million people are locked down in Xi'an and 1.1 million in Yuzhou. The lockdown of Anyang followed the confirmation of two cases of the omicron variant on Monday that are believed to be linked to two other cases found Saturday in the city of Tianjin. It appears to be the first time omicron has spread in China beyond people who arrived from abroad and their immediate contacts. Residents are not allowed to leave their homes, non-essential vehicles are banned from streets and stores have been ordered shut except for those selling necessities.