A coronavirus isolation centre is prepared at the Sani Abacha stadium in Kano, Nigeria. Photograph: Aminu Abubakar/AFP via Getty Images

Nigeria’s president has announced an immediate two-week lockdown in Kano, the largest city in the north, after local reports of a big rise in deaths in recent days.

The federal government would deploy “all the necessary human, material and technical resources” to support Kano state, Muhammadu Buhari said on Monday night.

Doctors in Kano say they have seen a surge in fatal cases of pneumonia. But local authorities have denied that Covid-19 is responsible, variously blaming malaria, meningitis, hypertension, and other illnesses for the increased mortality.

By Monday evening there were only 32,138 reported cases of Covid-19 in Africa and 1,438 confirmed deaths.

However, limited testing facilities, combined with poor infrastructure and communications, means this is likely to be a significant underestimate of the true extent of the disease.

Local media reports from Kano of hundreds of deaths in recent days have raised the possibility of major outbreaks of the lethal disease going undetected for weeks across Africa.