Nigeria has declared three days of national mourning following the crash of a Nigerian Air Force aircraft in Ondo State that killed all 32 people on board.

President Bola Tinubu ordered national flags to be flown at half-mast in honour of the victims after the aircraft crashed near a naval base in Igbokoda on Monday.

The ATR-42 aircraft was carrying 25 passengers and seven crew members on a routine flight from Benin City to Lagos when it went down.

The aircraft reportedly disappeared from radar at about 9.13am local time before its wreckage was located in a swampy area near the naval base.

Tinubu directed the Nigerian Air Force to conduct a full investigation into the circumstances surrounding the crash and establish measures to prevent similar accidents in the future.

Authorities said the identities of the deceased officers would be released after their families had been notified.

The crash is among the deadliest military aviation accidents reported in Nigeria in recent years, prompting mourning across the country as authorities begin investigations into what caused the aircraft to go down.