A controversial painting showing South Africa’s President Jacob Zuma with his genitals hanging out has been vandalised in an art gallery.The BBC’s Andrew Harding at the gallery in Johannesburg said a man covered the art work in black and red paintIt comes as the governing ANC was asking the High Court to force the Goodman Gallery to remove the painting.The $14,000 (£9,000) 1.85m-high Soviet-style, red black and yellow acrylic painting had already been sold.Called The Spear, the painting is by Brett Murray, who is known for his political and provocative work.President Zuma’s head and his genital area have now been obscured by red and black paint.Our correspondent says he saw one man wielding the paint brush, who was then pounced on by security guards and head-butted at one point.Another man was also identified as being behind the attack."I’m doing this because the painting is disrespectful to President Zuma,” one of the men told the BBC.The African National Congress has described the work as "rude, disrespectful and racist”.Earlier a crowd of ANC supporters had gathered near the court house in Johannesburg where the ruling party’s challenge to get to the painting removed was being heard.It was decided that a full bench of the High Court would hear the case on Thursday."This is a matter of great national importance,” the South African Press Association quotes Judge Kathree Setiloane as saying.