The authorities in Nigeria's commercial capital, Lagos, have made the wearing of face masks mandatory in a bid to halt the spread of coronavirus.

The number of confirmed cases in the city stands at 731, more than half of the total confirmed cases in Nigeria.

The government said the failure to use face masks in public places in the city will attract penalties.

Lagos State Governor Babajide Sanwo-Olu said the government will distribute face masks to residents.

The state has a population of about 20 million people and many of them live in cramped housing conditions.

Lagos state and neighbouring Ogun state as well as the capital, Abuja, have been in lockdown for a month.

President Muhammadu Buhari is expected to decide later today on whether the lockdown will be extended.

Some 40 people have died of the virus in Nigeria as the number of total confirmed cases surged to 1273 as at Sunday night.