Police patrol boats and rescue teams searched waterways around the crash site on October 6, while an excavator moved through the waterlogged area. Rescue personnel and residents also gathered along the riverbank.

The Nigerian Air Force ATR-42, with tail number NAF 931, crashed near a naval base in Igbokoda on October 5 while flying a routine mission from Benin to Lagos.

Volunteer rescuer Akinten Omotaeremi said reaching the crash site proved difficult because of the terrain.

"It took the Nigerian Navy first responder team about fifteen minutes before they got to the crash site," Omotaeremi explained. "There was no road to the site. It took a while before we could get to the crash site - we had to clear vegetation to get there. When we got there, we saw a big impact site in the swamp."

Another rescuer, Omotayo Orimisan, said the aircraft could not be seen when the team reached the impact site.

"We didn't see the plane at all at the crash site, but when we dipped sticks in the crater at the impact site, we could feel it touching something, but we didn't see it," he said, adding that human remains had been sighted.

Eyewitness Erejuwa Sunday said the pilot appeared to manoeuvre the aircraft away from the town centre before the crash.

"The pilot manoeuvred the plane away from the town centre. I thought he probably did that to avoid a crowded place that could get homes destroyed or get people killed," he said.

The Nigerian Air Force confirmed that 20 passengers and five crew members were aboard the aircraft and that no survivors had been found. The figure corrected an earlier government report that put the number of people on board at 32.

President Bola Tinubu declared three days of national mourning and ordered an investigation into the cause of the crash.

Specialist equipment has been deployed to help recovery teams retrieve wreckage from the swamp.