(GIN) – Calls for the resignation of President Jacob Zuma cut short a carefully planned May Day speech and exposed the deepening rift within the historic AFC party.

President Zuma, according to eyewitnesses from the scene, was shouted off the stage as he was about to address his long-time allies in the country’s biggest trade-union federation.

According to one poll, the President, now finishing eight years in office, is supported by only 20 percent of South Africans in the seven biggest cities. In the 23 years since apartheid ended and democracy began, it was the first time that an ANC leader was booed off the stage at a May Day rally, analysts said.

Two other senior ANC officials who support Mr. Zuma were similarly jeered and drowned out by union members when they attempted to speak at separate May Day rallies in other cities on Monday, while two of his ANC rivals were cheered at their own May Day events.

Blade Nzimande of the ANC’s Communist Party, said what happened at the aborted May Day event in Bloemfontein sends a strong message to alliance leaders. “I think we should use this as the ultimate wake up call,” he said sadly.

Zuma’s downfall was hastened by a recent cabinet purge and his decision to sack his widely respected finance minister. Frustrations with a sinking economy, corruption scandals and intimidation of the party’s critics fueled the shouts of “Zuma must go” and “Zuma must fall” even from the Congress of South African Trade Unions – once a formal alliance partner of the ruling ANC party.

Deputy president Cyril Ramaphosa and a presidential hopeful, has been increasingly critical of the appearance of unbridled government corruption. He is seeking a judicial inquiry into allegations that Mr. Zuma’s close friends and business allies, the Gupta brothers, controlled government appointments and offered bribes to senior officials.

As the divisions grow deeper within the ANC and its traditional allies, Mr. Zuma may find it increasingly difficult to orchestrate a handover to his chosen successor, his former wife, Nkosazana Dlamini-Zuma. And there are mounting fears that his loyalists could resort to violence to ensure his control over the country.

In a harbinger of things to come, last month tens of thousands of South Africans marched in cities and towns to demand the President’s resignation on a day when the country’s credit rating was downgraded to junk status by another major agency.

The anti-Zuma protests were the biggest in South Africa in years. The government estimated that about 60,000 protesters marched on Friday, everywhere from big cities to small towns, although organizers said the number was much higher.

Among those in the protests were members of several opposition parties, many civil-society groups, trade unions, business executives, the ruling party’s alliance partners in the Communist Party, former President Mandela’s granddaughter Ndileka, and even the 85-year-old Nobel Peace Prize winner, retired archbishop Desmond Tutu, who is in frail health.

Tutu and his wife Leah joined protestors outside the retirement home him and his wife Leah are staying in. The Desmond and Leah Tutu Legacy Foundation tweeted a quote by the Archbishop, saying: “We will pray for the downfall of a government that misrepresents us.”