A masked student re-enters high high school in Wuhan Wednesday, after a 100 day break due to the pandemic. FEATURE CHINA-BARCROFT MEDIA VIA GETTY IMAGES

Authorities in China have sealed off two cities south of Beijing as part of moves to contain the country’s largest COVID-19 outbreak in six months.

This involved cutting transport links and banning millions of residents from leaving the cities.

Mass testing, local lockdowns and travel restrictions have been employed by Chinese authorities to snuff out the outbreak of the disease since its emergence in Wuhan in late 2019, Aljazeera reports.

Last week Hebei province in northern China experienced 127 new COVID-19 cases and 183 asymptomatic infections.

Shijiazhuang, a city of about 11 million in the province has the majority of the confirmed new cases.

Nine confirmed cases were in the neighbouring city of Xingtai, whose area contains seven million people.

On Friday, authorities in Hebei province banned residents of both cities from leaving unless absolutely necessary.

Officials strictly control the movement of people and vehicles, with all residential estates placed under “closed management”, which is a lesser lockdown.

The residents of the province have also been banned from entering Beijing or leaving the province unless absolutely necessary.

“The outbreak was imported from abroad, but the exact origins are currently under in-depth investigation by state, provincial and municipal experts,” said Li Qi, head of the Hebei Centre for Disease Control and Prevention, at a press briefing on Friday.

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