Many residents in the city of 26 million have been confined to their homes for up to three weeks as China maintains its “zero-Covid” strategy of handling outbreaks with strict isolation and mass testing.

But people living under the restrictions have described an increasingly desperate situation, with families unable to leave their homes or obtain food and daily necessities, while people who test positive for the coronavirus have been forced into mass quarantine centers where conditions at times have been called crowded and unsanitary.?

The State Department said the order announced late Monday is an upgrade from the “authorized” departure advisory last week that made the decision voluntary. The order covers non-emergency U.S. government employees at the consulate in Shanghai and their family members. Consular officers will remain on duty at the consulate.?

“Our change in posture reflects our assessment that it is best for our employees and their families to be reduced in number and our operations to be scaled down as we deal with the changing circumstances on the ground," the announcement said.

The State Department also issued a series of advisories for Americans in Shanghai, including that they ensure they have a “sufficient supply of money, medication, food, and other necessities for your family in the event of sudden restrictions or quarantine."?

China's government and the entirely state-controlled media are growing increasingly defensive about complaints over the COVID-19 prevention measures.?

Beijing responded angrily to last week's voluntary departure advisory, with Foreign Ministry spokesperson Zhao Lijian saying China was “strongly dissatisfied with and firmly opposed to the U.S. side's groundless accusation against China's epidemic response.”?

In that announcement, the State Department advised Americans to reconsider traveling to China due to “arbitrary enforcement” of local laws and Covid-19 restrictions, particularly in Hong Kong, Jilin province and Shanghai. U.S. officials cited a risk of “parents and children being separated.”

Despite that, and indications the hardline policy is being dictated by head of the ruling Communist Party Xi Jinping, China has rejected any notion that its response is political in nature. Xi has demanded social stability above all else in the runup to a key party congress later this year at which he is expected to bestow on himself an unprecedented third-term as party leader.?

Shanghai authorities also say they have secured daily supplies for residents, following complaints about deliveries of food and other necessities being unavailable or inadequate to demand.

Shanghai says it will gradually lifted some restrictions on neighborhoods where no new infections have been reported over the past two weeks. Residents will be able to travel around their districts but not meet in groups. Others will be restricted to their immediate neighbourhoods.