The World Health Organisation's chief scientist has said the Delta variant of Covid-19, first identified in India, is becoming the globally dominant variant of the disease, Reuters reports.

"The Delta variant is well on its way to becoming the dominant variant globally because of its increased transmissibility," Soumya Swaminathan told a news conference.

Britain has reported a steep rise in infections with the Delta variant, while Germany's top public health official predicted it would rapidly become the dominant variant there despite rising vaccination rates.

The Kremlin also blamed a surge in Covid-19 cases on reluctance to have vaccinations and "nihilism" after record new infections in Moscow, mostly with the new Delta variant, fanned fears of a third wave.