The World Bank is helping to facilitate a deal between Switzerland and Nigeria which would see the former returning around US$320 million in assets that had been seized from the family of former military ruler Sani Abacha, the Swiss government said in statement.

“In accordance with policy on the repayment of national assets taken illegally, Switzerland has agreed with Nigeria and the World Bank to return nearly US$321 million, for the benefit of the Nigerian people,” the statement outlined.

Corruption watchdog Transparency International has accused Abacha of stealing as much as US$5 billion of public money during his five-year reign of the oil-rich country, from 1993 until his death in 1998. In April 2005, Abba Abacha, the former military ruler’s son, was charged by a Swiss court with money-laundering, fraud and forgery. He had been extradited from Germany and spent 561 days in custody.

Transparency International has accused Abacha of stealing as much as US$5 billion of public money

The Nigerian government and the Abacha family reached an agreement in 2014 in terms of which the West African country would get back the funds, which had been frozen in 2006, in return for dropping a complaint against Abba Abacha.

Read: No place to hide: What reformed Swiss banking law and monitoring of local funds transfers means for grand corruption in Africa

“The project will strengthen social security for the poorest sections of the Nigerian population. The agreement also regulates the disbursement of restituted funds in tranches and sets out concrete measures to be taken in the event of misuse or corruption,” the Swiss government said.

The latest development is that Switzerland, Nigeria and the World Bank have agreed the funds will be repatriated via a project supported and overseen by the World Bank. This has been confirmed by the Swiss government.

The fight against corruption was “one of Switzerland’s priorities”.

When the agreement was announced, Swiss Foreign Minister Didier Burkhalter stated that the fight against corruption was “one of Switzerland’s priorities”.

In Nigeria, President Muhammadu Buhari has been leading a purge of corruption since taking office in 2015, vowing to recover what he said were “mind-boggling” sums of money that had been stolen over many decades.