The funds were traced to more than 50 bank accounts, it said.

Humanitarian Affairs and Poverty Alleviation Minister Betta Edu was initially suspended in January over the alleged diversion of $640,000 of public money into a personal bank account.

President Bola Tinubu then ordered an investigation into her ministry.

At the time Dr Edu, 37, denied any wrongdoing. Her office said she had approved the transfer into a personal account, which was not in her name, but said it was for the "implementation of grants to vulnerable groups".

The Economic and Financial Crimes Commission (EFCC) said during its nearly six weeks of investigating so far, it had found "many angles" to examine.

"As it is now, we are investigating over 50 bank accounts that we have traced money into. That is no child's play. That's a big deal," its chairman Ola Olukoyede said in the latest edition of the agency's monthly e-magazine, EFCC Alert.

He urged Nigerians seeking redress to give the agency time to finish its probe thoroughly.

"We are exploring so many discoveries that we have stumbled upon in our investigation. If it is about seeing people in jail, well let them wait, everything has a process to follow," he said.

The EFCC chairman gave an assurance that the recovered funds were "already in the coffers of the federal government".

The suspension of a minister is a rare occurrence in Nigeria.