Fresh criminal charges against Angolan billionaire Isabel dos Santos are politically motivated, she has insisted.

Angola's public prosecutor has charged Ms Dos Santos with 12 crimes, including embezzlement and fraud, reports said.

The charges relate to Ms Dos Santos' time as chair of a state-owned oil firm.

Previously described as Africa's richest woman, Ms Dos Santos ran Sonangol from 2016 to 2017.

She is the daughter of former Angolan President José Eduardo dos Santos, who led the south-west African country for 38 years until he stepped down in 2017.

Critics of Ms Dos Santos have long claimed she used her position of influence to enrich herself at the expense of the state - allegations she has denied.

On Tuesday, Ms Dos Santos told Angolan radio station Rádio Essencial that "these lies have to end".

"I think it is time for the government and the republic's attorney general to take responsibility for the accusations they make because it's irresponsible to be managing a country based on fabricated lies," she said.

Earlier in the day, one of her lawyers, Dan Morrison, told the BBC: "Isabel dos Santos rejects these trumped-up charges by the Angolan government which have been launched as part of a sustained campaign of political persecution against her by President [João] Lourenço."

Under the presidency of Mr Lourenço, several of José Eduardo dos Santos' relatives have been prosecuted on various charges, which they deny.

In 2020, Angolan prosecutors charged Ms Dos Santos with embezzlement and money laundering.

Global police agency Interpol issued a "red notice" for the billionaire in 2022, asking global law enforcement authorities to locate and provisionally arrest her.

Ms Dos Santos has not been arrested since investigations against her began but she is subject to a number of asset freezes around the world.

On Tuesday, she said these restrictions had led her to struggle financially.

"I can't manage my accounts to pay for my children's studies, health care or house rent," she told Rádio Essencial.

Her lawyer, Mr Morrison, said: "Isabel is presently engaged in court proceedings in various jurisdictions to clear her name.

"The aim of the Angolan authorities is to intimidate her from returning to Angola so she is unable to run for political office."

Ms Dos Santos has mooted running for Angola's presidency in various media interviews over the past few years.

The most recent indictment against Ms Dos Santos was filed on 11 December, Portuguese news agency Lusa reports, but the Angolan attorney general's office told the BBC it could not comment on the matter as it was "under judicial secrecy".

Ms Dos Santos has previously been described as Africa's richest woman, with an estimated fortune of $2bn (£1.6bn). She is no longer included on Forbes' rankings of the world's wealthiest people because her assets are under dispute in various territories.