China reported 125 new Covid-19 cases on the mainland Monday, up from 96 cases a day earlier, in its latest outbreak of the disease.

The wave is part of an expanding Covid-19 Delta variant outbreak in the country that is becoming increasingly severe, following months of little to no locally transmitted cases.

Among the new confirmed infections, 94 were locally transmitted, up from 81 a day earlier, while the remainder was imported from abroad, the National Health Commission said.

Most locally transmitted infections were reported from the central province of Henan and the eastern province of Jiangsu.

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China's case tally stood at 93,826 since the outbreak began, and fatalities stayed at 4,636.

The current wave of Covid-19 in China started in the eastern city of Nanjing, when nine airport cleaners at the Lukou International Airport tested positive during routine testing on July 20.

Viral genome sequencing has found all strains to be the fast-spreading Delta variant of the Covid-19 virus, officials confirmed.

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Variants are continuing their progression, as the Alpha variant was seen in 180 countries, territories or areas, and 13 new countries, territories or areas reported cases of the Delta variant.

While the Alpha variant is still detected more often than its counterpart, the Delta variant is believed by the World Health Organization to be 50% more transmissible and might become the dominant form of the virus in the next few months.