Shanghai has reported a new record of more than 26,000 COVID cases in 24 hours as officials seek to reassure residents they have secured enough supplies of basic necessities.
Other cities around China, including the southern city of Guangzhou, are introducing new restrictions and building makeshift hospitals as the government continues to stick to its "dynamic zero COVID policy".
China's official news agency Xinhua said on Sunday that to ease the policy would be "disastrous".
"China's medical system would risk a collapse leading to enormous loss of life if it gives up on epidemic prevention and control," the agency said.
Shanghai has been in lockdown since 28th March.
Videos circulating on social media show crowds of angry residents gathering in front of police to demand supplies in Kangting community.
The city has built more than 100 makeshift hospitals, with capacity for 160,000 patients.
Anyone who tests positive for COVID must be sent to one of those hospitals, rather than isolate at home. Conditions in the hospitals vary massively.
Videos appeared to show half completed centres, with mattresses strewn on the floor and unsanitary toilet conditions.
City official Gu Honghui said Shanghai would make "dynamic" adjustments to lessen the impacts of restrictions on citizens.
The Shanghai government has announced plans for an exit from the current measures.
Residential compounds have been divided into three types: areas that are completely sealed off, others subject to controls, and "prevention areas" that can open up after two weeks without a positive case.
Residents must remain in their district, but can move around within that area.
Guangzhou, an export hub in the south, announced that it would suspend in-person teaching for students and start mass testing its 18 million residents.
In the capital Beijing, a high risk area was put under lockdown over the weekend after it reported eight COVID cases over the last two weeks.