The locked-down Chinese city of Xi'an has tightened Covid-19 controls to the “strictest” level, banning residents from driving cars around town in an effort to control the country's worst outbreak in 21 months, AFP reports.

Xi'an — where 13 million residents are facing their fifth day of home confinement — is at the centre of a flare-up that has pushed nationwide daily infections to their highest numbers since March last year.

Restrictions tightened further on Monday as Xi'an announced it would impose the “strictest social control measures”, according to a city government social media account.