Johannesburg: South African Finance Minister Pravin Gordhan said in court documents on Monday that a trio of Indian-born businessmen was waging an “organized campaign” against him and the Treasury, the latest salvo in a legal and financial battle that has unsettled investors.

The Gupta brothers, who deny allegations that they wield excessive influence over President Jacob Zuma, had themselves accused Gordhan in a court filing 10 days ago of conducting a vendetta against them and trying to damage their business.

The dispute is an unwelcome distraction for the finance minister, whose own relationship with Zuma has been tense, as he tries to persuade ratings agencies not to downgrade South Africa to ‘junk’ status in response to stuttering economic growth.

Gordhan said in his affidavit that the Guptas’ Jan. 20 court filing was part of a “systematic and highly organised campaign by the Gupta family and its associates against the National Treasury, myself and other targets.” He denied having a vendetta against them.

The Gupta brothers’ lawyer was not available to comment.

A previous filing by Gordhan last October had said that 6.8 billion rand (Dh1.8 billion or $500 million) in payments made by the three brothers, and companies they control and other individuals with the same surname, had been reported to authorities as suspicious since 2012.

The Guptas said this statement was “riddled with factual and legal errors”.

Gordhan has asked a court for a declaratory judgment that he cannot interfere with decisions by South Africa’s major banks to cut their ties with businesses owned by the Guptas. He has said they repeatedly asked him to intervene to have their accounts reopened.

Between December 2015 and April 2016, FirstRand, Standard Bank, Nedbank and Barclays Africa all terminated the accounts of companies controlled by the Gupta family’s Oakbay Investments.

Allegations that the Guptas wielded undue influence over Zuma were investigated last year by the Public Protector, a constitutionally mandated anti-corruption watchdog.

It did not make conclusive findings but recommended that the president order a judicial inquiry to investigate the allegations, which has yet to happen. Zuma has said the Guptas are his friends, but denies anything improper about the relationship.