Some residents under quarantine in the Chinese city of Xi'an have resorted to bartering supplies in recent days, as worries of food shortages continue.

Posts on social media show residents swapping supplies and even tech gadgets in exchange for food.

About 13 million have been confined to their homes since 23 December, and presently cannot leave to buy food.

In recent days many have taken to social media with numerous complaints.

Authorities have been providing free food to households, but some have said their supplies are running low or that they had yet to receive aid.

Videos and photos on social media site Weibo showed people exchanging cigarettes for cabbage, dishwashing liquid for apples, and sanitary pads for a small pile of vegetables.

One video showed a resident appearing to trade his Nintendo Switch console for a packet of instant noodles and two steamed buns.

"People are swapping stuff with others in the same building, because they no longer have enough food to eat," a resident surnamed Wang told Radio Free Asia. The news outlet also reported that another man had wanted to trade a smartphone and tablet for rice.

Some were more optimistic though, and commented on how "touched" they were by their neighbours' kindness of sharing their supplies with them.

Xi'an is at the epicentre of China's current Covid outbreak, and local authorities have enacted drastic measures which have attracted significant criticism online.

In a recent incident, residents in the Mingde 8 Yingli housing compound in the south of the city were reportedly told just after midnight on 1 January that they had to leave their homes and go to quarantine facilities.

Netizens were also shocked by an unverified post that went viral on Monday. A Xi'an resident claimed their father had died after he suffered a heart attack and was turned away from a hospital due to the city's Covid situation. The hospital has yet to respond.

The city's outbreak is the worst China has seen in months as it continues to pursue a zero Covid strategy, where it seeks to stamp out the virus.

On Tuesday, authorities moved to put a second city into full lockdown after the detection of three asymptomatic cases.

Around 1.1 million residents in Yuzhou - a city located 500km (310 miles) away from Xi'an - will now have to stay in their homes.

As of Monday evening, almost all vehicles have been banned from the roads, and all shops and businesses - apart from supermarkets supplying essentials - have been told to close.

The strict measures come ahead of the Lunar New Year and the Winter Olympics due to be held in Beijing next month.