Nigeria's finance minister says kidnappers who held her mother hostage for five days had demanded her resignation, suggesting the abduction had a political motive.
Ngozi Okonjo-Iweala, one of Nigeria's most prominent figures, has been in a highly publicised struggle with fuel importers over payment of subsidies, with government officials delaying payments to allow for verification of claims.
In her first public comments on the kidnapping ordeal, Okonjo-Iweala said her 83-year-old mother, Kamene Okonjo, was held 'for five days without food or water'. Her release was announced on Friday.
'While she was in their custody, the kidnappers spent much of the time harassing her. They told her that I must get on the radio and television and announce my resignation,' Okonjo-Iweala said in a statement on Monday.
'When she asked why, they told her it was because I did not pay 'Oil subsidy money',' the statement said.
The finance minister did not take questions and made no comment as to whether a ransom was paid. The circumstances surrounding her mother's release remain unclear.
A parliamentary probe earlier this year found Nigeria, Africa's top oil producer, lost $US6.8 billion ($A6.5 billion) through the subsidy program between 2009 and 2011. The subsidies are designed to hold petrol prices low.
The probe detailed what has long been suspected in Nigeria, describing a lack of accounting, overpayments, wilful disregard for regulations and outright incompetence in managing the program.
Fuel importers have voiced anger at what they term the government's outstanding payments, while Okonjo-Iweala has been at the forefront of a campaign to ensure all subsidy claims are legitimate.
'President Goodluck Jonathan is determined to do the right thing. We have had a lot of support. We will continue to do the right thing,' she said.