Nigeria's former oil minister Diezani Alison-Madueke was arrested in London on Friday, a source from Nigeria's presidency circle and another with links to her family said.
She was minister under former president Goodluck Jonathan until May 2015.
A police spokesman in London said he had no record of such an arrest. The National Crime Agency did not immediately respond to a request for comment.
(Reporting By Felix Onuah and Julia Payne, Additional reporting by Reuters UK newsroom; Editing by Janet Lawrence)