Xian in northwest China has reported an increase in daily Covid-19 infections and local companies have curtailed activity as the country's latest Covid-19 hot spot enters its third day of lockdown, Reuters reports.

The city of 13 million has detected 75 domestically transmitted cases with confirmed symptoms, its highest daily count of the year and reversing the previous day's decline, official data showed.

Xian, which has started a new round of mass testing, has announced no infections caused by the Omicron variant. Nationwide, China has reported a handful of Omicron infections among international travellers and in southern China.