A leading scientist who identified a new coronavirus variant in Nigeria has cautioned against comparisons with new strains found in South Africa and the UK.

Christian Happi, head of the African Centre of Excellence for Genomics and Infectious Diseases in Nigeria, said more studies were needed to see whether the country's new variant was linked to a recent spike in infections.

Nigeria's new strain was found in two out of two hundred samples collected between August and October.

South Africa said its new variant could explain a recent increase especially affecting younger people.

It has become the first country on the continent to register more than one million Covid-19 cases.

Last week, South Africa recorded a daily average of 11,700 new infections - a rise of 39% on the previous week - and from Wednesday to Friday, the daily number of new cases was above 14,000.

Nigeria recorded a 52% increase in cases last week, Reuters news agency reported.

It has recorded more than 82,000 cases and 1,200 deaths.