The sharp rise in the toll came as bodies were recovered nearly 10 kilometres (six miles) from the town, where more than 250 buildings were levelled and two bridges were swept away, a spokesman for the Niger State Emergency Management Agency, Ibrahim Audu Husseini, told AFP.
Husseini said the toll could rise further, with bodies being swept down the powerful Niger River.
Gideon Adamu, head of the Red Cross in Niger state, said that search teams were heading toward Jebba, on the opposite side of the waterway’s swampy banks.
Mokwa was hit by torrential rains Wednesday night into Thursday, with the flooding displacing more than 3,000 people, Husseini said. There were 121 injured in hospital, Adamu said, and more than 100 people were missing.
Nigeria’s rainy season, which usually lasts six months, is just getting started for the year.
Heavy rains and poor infrastructure lead to flooding that wreaks havoc every year, killing hundreds of people across the west African country.
Scientists have also warned that climate change is fuelling more extreme weather patterns.
Residents in the town, around 350 kilometres by road from the capital Abuja, were still searching for relatives. In some cases, families were missing a dozen people.
“We can’t give up the search as long as there are families crying out,” said Adamu, the Red Cross chief.
According to a tally provided by Husseini, 151 people were killed, 3,018 were displaced, 265 houses were destroyed and two bridges were washed away in the busy market town.
Mohammed Tanko, 29, a civil servant, pointed to a house he grew up in, telling reporters Friday: “We lost at least 15 from this house. The property (is) gone. We lost everything.”
Floods in Nigeria are exacerbated by inadequate drainage, the construction of homes on waterways and the dumping of waste in drains and water channels.
Complicating the search for missing persons was the presence of a large group of travellers staying overnight in a Mokwa mosque when the rains hit, Adamu said. The building collapsed and it was still unknown where the people had been travelling from.
President Bola Tinubu said the disaster response was being aided by security forces. (AFP)