China coronavirus cases on Russia border spark lockdowns, tests

China has put one northern city in lockdown and launched citywide coronavirus testing in another, after two local infections involving workers at a port and trade zone respectively, authorities have said.

There was one new case each in Dongning and Suifenhe, which both sit on the country's border with Russia.

In Dongning, a 40-year-old maintenance worker at a port tested positive on Thursday, triggering the latest measures.

Officials there said Saturday it would enter "wartime mode" -- temporarily suspending public bus services and road transport, while requiring anyone leaving the city to produce a negative Covid-19 test from the preceding 24 hours.

Schools will suspend classes and dine-in will be banned at restaurants, while in higher-risk areas only one member of each household will be allowed to leave the home once every two days to buy daily necessities -- for no longer than two hours each time.

In the Suifenhe case, a 39-year-old man who works as a loading and unloading worker at a trade zone tested positive.

Both cities on Friday announced the launch of citywide testing, expected to be completed in three days.

China -- where the virus first surfaced late last year -- has largely brought domestic transmission under control but recently reported local outbreaks in several cities.

State media blamed the recent clusters on imports of frozen food and other shipments.

After a recent outbreak in Chengdu, officials said the virus was found on food stored in an elderly couple's fridge.

There is currently no evidence that people can catch Covid-19 from food or food packaging, according to the World Health Organization.