Protesters in South Africa have called for President Jacob Zuma to resign after the release of a report that found "possible evidence of corruption" at top government levels.

The long-awaited report was published on Wednesday after Zuma's lawyers made a surprise U-turn earlier in the day and withdrew an application seeking to delay its release.

It probed accusations that the president allowed the Guptas, a wealthy Indian business family, undue political sway, including letting them choose some cabinet ministers.

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In the report, Thuli Madonsela,  South Africa's former public protector, recommended that an independent commission of inquiry headed by a judge be set up within 30 days to investigate the issue fully. 

South Africa: Corruption report increases pressure on Zuma

"Basically the report implicates President Zuma, the Gupta family and other senior officials," said  Al Jazeera's Haru Mutasa, reporting from Pretoria. 

"But the public protector admitted in the report that she didn't have enough resources to further investigate the issue, so she is recommending that president Zuma sets up a commission of inquiry headed by a judge within 30 days."

Madonsela, a constitutionally mandated anti-graft official, said that the commission should present its findings and recommendations to the president within 180 days.

"Some people feel that the president has been given more time to look into the matter, but on the whole the opposition seems for now to be satisfied with the report," said our correspondent.

"The president won't choose the judge himself. So the opposition feels, or at least hopes, that the judge will be fairly independent."

'Unfair advantage'

The carefully worded report stopped short of asserting that crimes had been committed, saying the watchdog lacked the resources to reach such conclusions.

But the 355-page report called for additional investigation into potential conflicts of interest, including a case surrounding a mining company called Tegeta, co-owned by the Guptas and the president's son Duduzane Zuma.

The report says Tegeta was given lucrative government contracts to finance its expansion, claiming that the company may have been officially supported by a government minister in its bid to purchase a mine.

Police fired rubber bullets and used water cannon to disperse protesters who tried to storm Zuma's office [Siphiwe Sibeko/Reuters]

It raised questions whether Mining Minister Mosebenzi Zwane travelled to Switzerland with the Guptas last November to help them "seal the deal" for Tegeta to buy a mine from commodities giant Glencore.

"If Zwane travelled in his official capacity to support Tegeta's bid to buy the mine, his conduct would give Tegeta an unfair advantage over other interested buyers," the report said.

"It is potentially unlawful for the minister to use his official position of authority to unfairly and unduly influence a contract for a friend or, in this instance, his boss’s son, at the expense of the State. This scenario would be further complicated if his actions were sanctioned by the President," it added.

Zuma denies providing special favours for wealthy friends.

Anti-Zuma protests

South Africa's ruling  party, the African National Congress (ANC), said on Wednesday that it was studying the report and would comment on it on Thursday.  

Zuma, 74, has survived a string of damaging controversies, but faces increasing criticism as the economy stalls and after his party suffered unprecedented losses in local polls.

Some factions of the ANC, former anti-apartheid activists and business leaders have all recently called for him to stand down before his term ends in 2019.

Outside the High Court, demonstrators carried 'Zuma must go' placards. [Herman Verwey/EPA]

Earlier on Wednesday, thousands of opposition party supporters, unions and civil groups marched through Pretoria to protest against Zuma's presidency.

Police fired rubber bullets and used water cannon to disperse protesters who tried to storm Zuma's office in the city. Outside the High Court, demonstrators carried "Zuma must go" placards.

The marches were originally planned to show support for Pravin Gordhan, the finance minister, who was due in court on Wednesday on separate corruption charges that many analysts see as an attempt by Zuma loyalists to remove him.

But prosecutors dropped the charges on Monday in another twist to a power struggle that has exposed deep tensions in the ANC.

READ MORE: South Africa's Zuma denies rich family influencing him

The ANC, the party that Nelson Mandela led in the fight against apartheid, has held power since white-minority rule ended in 1994.

The Gupta family - brothers Ajay, Atul and Rajesh - built an empire in mining, transportation, technology and media after arriving in South Africa from India in the early 1990s.

Early this year, Mcebisi Jonas, South Africa's deputy finance minister, accused the Gupta family of offering him the job of finance minister, something he said he rejected.

Zuma last month said he was not given enough time to respond to the watchdog's questions and blocked the release of the report. 

Earlier on Wednesday, the presidency released a statement saying Zuma had withdrawn his application to delay the release of the report in the interests of justice.

"In the interest of justice and speedy resolution of the matter, the president decided to withdraw his application," the presidency said.

"The president will give consideration to the contents of the report in order to ascertain whether it should be the subject of a court challenge."

Source: Al Jazeera News And News Agencies