Nigeria's economic crimes commission said it recovered nearly $500-million in proceeds of crime last year and secured more than 4 000 criminal convictions, its highest since the agency's inception more than two decades ago.

Africa's biggest energy producer, Nigeria has struggled for decades with endemic corruption, which many Nigerians say contributes to widespread poverty in the country.

The Economic and Financial Crimes Commission (EFCC), which investigates and prosecutes corruption in Nigeria, said in a report on Monday that some of the recovered money was reinvested in government projects.

Nigeria is ranked 140 out of 180 on Transparency International's latest Corruption Perception Index.

Besides cash, the EFCC said it also seized 931 052 metric tons of petroleum products, 975 real estate properties and company shares.