Africa's richest woman, Isabel dos Santos, has denied fraud and plans to sue the Angolan government.

Ms Dos Santos in a statement on Thursday said the accusations made by Attorney General Helder Pitta Gros on Wednesday were false and politically motivated.

Mr Gros said that Ms Dos Santos was being provisionally charged with "money laundering, influence peddling, harmful management... [and] forgery of documents, among other economic crimes".

Ms Dos Santos, who was considering running for presidency, said the accusations were political.

"The allegations which have been made against me over the last few days are extremely misleading and untrue. This is a very concentrated, orchestrated and well-coordinated political attack, ahead of elections in Angola next year. It is an attempt to neutralise me and to discredit the legacy of President Dos Santos and his family," she wrote.

Leaked documents showed how Ms Dos Santos got access to lucrative land, oil, diamond and telecoms deals when her father, Jose Eduardo dos Santos, was president.

"Stolen documents have been leaked selectively to give a false impression of my business activities. I am a private businesswoman who has spent 20 years building successful companies from the ground up, creating over 20,000 jobs and generating huge tax revenue for Angola. Last year my businesses paid over $100m in tax. I have always operated within the law and all my commercial transactions have been approved by lawyers, banks, auditors and regulators," she wrote.

A banker, Nuno Ribeiro da Cunha, who was named as a suspect was found dead in his house in Lisbon, Portugal.

He managed the account of oil firm Sonangol, formerly chaired by Ms Dos Santos, at the small Portuguese lender EuroBic.

Mr Da Cunha was found dead at one of his properties in Lisbon. A police source told Portuguese media that "everything points to suicide".