At least 274 inmates have escaped from a prison in Nigeria’‘s Borno state following heavy flooding, the Nigerian Correctional Service said, as aid agencies reported more than 1,000 people had died across western and central Africa.

Initially, 281 inmates escaped while they were being transferred to “a safe and secure facility” but seven were recaptured later, Nigerian Correctional Service spokesman Abubakar Umar said in a statement on Sunday.

“The flood brought down the walls of the correctional facilities, including the medium security custodial center Maiduguri (MSCC) as well as the staff quarters in the city,” he said.

Umar added that the service was aware of escapees’‘ identities, including their biometrics, and had made this information “available to the public.”

The search for the inmates was ongoing, he said.

Weeks of flooding across Nigeria have led to 269 deaths and displaced more than 640,000 people, according to the latest data from the country’‘s disaster management agency NEMA.

Northern Nigeria has been the most affected by the floods, the data showed. Borno state is in the northeast of the country.

Last month, the Nigeria Hydrological Services Agency (NIHSA) also warned of the rising water levels of the Niger River, one of the country’‘s largest rivers, urging states to be on alert.

Extreme rainfall events are expected to increase in frequency and intensity across almost all of Africa, including Nigeria, as human-caused climate change heats the planet, projections from the Intergovernmental Panel on Climate Change show.

Around 4 million people have been affected by floods across Nigeria and its west and central African neighbors with surging waters leaving a trail of devastating effects, including multiple human casualties.

In Chad, at least 487 people have lost their lives from flooding, according to Chadian media, with 265 others killed in similar flood incidents in Niger. Another 55 people have died in Mali, aid groups reported.

In Cameroon, up to 20 people have been reported dead from recent floods which have also impacted other parts of Africa such as the northeastern Sudan where at least 97 people have been killed, according to data by the UN Office for the Coordination of Humanitarian Affairs (OCHA).

On Wednesday, floodwaters that gushed from an overflowing dam in northern Nigeria engulfed a zoo and swept animals including crocodiles and snakes into nearby communities.