WATCH | Magashule supporters disrupt Joburg launch of 'Gangster State'

Protesters shouting their support for ANC secretary-general Ace Magashule disrupted the launch of Pieter-Louis Myburgh's book, Gangster State: Unravelling Ace Magashule's Web of Capture, in Johannesburg on Tuesday evening.

Singing and holding up posters declaring "#HandsOff SG Ace", they stormed into Exclusive Books in Sandton City.

The protesters shouted at customers, telling them: “Go! Go! Why are you prosecuting Ace Magashule? They can’t call us [k-word] any more; now they call us corrupt!”

The publishers of the explosive book, which implicates Magashule in state capture, earlier said they were unshaken by threats of legal action over the contents of the book.

"We further note Mr Magashule's threats to pursue legal action over the contents of the book. We will oppose any legal action that seeks to hide essential facts from South Africans about how our government is really being run," said Surita Joubert on behalf of Penguin Random House South Africa.

The book details Magashule’s murky dealings as a struggle activist in the 1980s and later as premier of the Free State - and his rise to one of the ANC's most influential positions.

This is a developing story.