Zambia's President Hakinde Hichilema has taken the extraordinary step of firing the entire board of the country's corruption-busting body, after they themselves were accused of corruption, which they deny.

It comes days after the head of the Anti-Corruption Commission (ACC), Thom Shamakamba, resigned from his post.

Both he and the country's solicitor-general - Marshal Muchende - were accused of taking kickbacks. Both men strongly deny the allegations.

Since Mr Hichilema came to power three years ago, the authorities have been investigating a number officials from the former government accused of graft.

Now, the explosive allegations are that ACC officials have been taking payments from politicians targeted by the probe in exchange for amnesty.

The whistleblower is a man called O’Brien Kaaba - who was once a board member of the ACC.

"Going by press reports, ACC, for example, has made legally senseless settlements immunising some of the most corrupt individuals, thereby shielding them from justice and accountability," he wrote earlier this week.

He said the same "immunity deals" under the former governing party, the Patriotic Front, were now being "used under the current government in a manner that shows no commitment to fighting corruption".

He said the ACC must be reformed, alleging that the rot goes beyond the four fired board members and affects the whole institution.

Mr Kaaba has been sued by Mr Muchende for defamation - a step that other figures could yet take.

A statement from Zambia's presidency said dissolving board was necessary "to renew the Anti-Corruption Commission's sacred mandate".

The statement announcing Mr Shamakamba's resignation was also issued by State House, leading some to speculate whether he had in fact been fired.