Nigeria's finance minister said Monday that the 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 battle with fuel importers over subsidy payments that government officials have delayed amid allegations the programme is plagued by mismanagement, overpayment and rule-breaking.
In her first public comments on the kidnapping ordeal, Okonjo-Iweala said in a statement that her 83-year-old mother, Kamene Okonjo, was held "for five days without food," after being taken in the southern, oil-producing Delta state.
Mother and daughter pic :vanguard
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.
"When she asked why, they told her it was because I did not pay 'Oil subsidy money,'" added Okonjo-Iweala, the former managing director of the World Bank.
She did not take questions after reading her statement 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 $6.8 billion (5.2 billion euros) through the subsidy programme 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 programme.
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 that all subsidy claims are legitimate.
The minister, who was also a candidate to head the World Bank earlier this year, said the attack on her family would not lead to a policy change in the government of President Goodluck Jonathan.
"For marketers whose transactions are proven to be fraudulent, the position of the Jonathan government is also clear: we cannot and we will not pay. We will not back down on this," her statement said.
Ransom kidnappings are a lucrative business in southern Nigeria, though such high-profile victims are rare.
Gangs have frequently sought expatriates working in the oil-producing Niger Delta for ransom kidnappings, but Nigerians from wealthy families have increasingly become their targets in recent years.
A 2009 amnesty deal in the Niger Delta led to a sharp drop in unrest in the region, but criminality remains widespread.