Hani’s monument consists of four marble columns symbolisng the pillars of the struggle against white power led by the African National Congress (ANC), in power since the advent of democracy in 1994.

A monument in honour of anti-apartheid hero Chris Hani has been vandalised in South Africa, a week after the controversial announcement of the early release of his far-right killer, sources from the municipality of Ekurhuleni where the monument dedicated to his memory is said on Tuesday.

“The monument was vandalised overnight from Saturday to Sunday. One of the pillars is badly damaged. One side collapsed and the lighting system was stolen,” Ekurhuleni spokesperson Zweli Dlamini told AFP news agency.

The ANC and its allies said in a joint statement they were “deeply saddened by the vandalism and desecration” of the monument, describing the incident as a “provocative attack”. According to them, the vandalisation was “tantamount to a continuation of Chris Hani's assassination in the grave”.

An investigation has been opened for theft and vandalism.

Hani, who was regarded as the most popular leader in South Africa after anti-apartheid icon Nelson Mandela, was the leader of the South African Communist (SACP) and a senior member of the armed wing of the ANC.

The 50-year-old activist, while picking up the newspapers outside his home, was killed at close range in his driveway on 10 April 1993 by the Polish immigrant Janusz Walus, who shot him in the chin, behind the ear, and in the chest.

Walus killed Hani in a failed attempt to derail South Africa’s transition from white-minority rule to democratic rule. At the time, delicate negotiations with the white power in view of the first democratic elections in the country were underway.

Tens of thousands of people attended Hani’s funeral, about a year before Mandela became the country’s first black president, heralding the end of apartheid - a legalised system of racial discrimination against black people.

Walus, now 69, had been sentenced to death but the new regime abolished capital punishment in 1994, and his sentence was commuted to life imprisonment. After nearly 30 years in prison, South Africa’s highest court granted him conditional release on November 21, saying he must be released from prison no later than December 1.

While Hani’s widow has denounced a “truly diabolical judgment”, the court’s decision to release Walus on parole has caused outrage in ANC circles. A demonstration against his release gathered dozens of people on Saturday at the call of the ANC, which said the decision had “pleased unrepentant apartheid perpetrators”.