South African police used stun grenades and water cannon today to disperse supporters of outspoken ANC Youth League leader Julius Malema, who faces a party disciplinary hearing that could derail his political career.
Scores of Mr Malema's supporters hurled rocks and beer bottles at police, burned African National Congress (ANC) flags and posters of President Jacob Zuma outside the party headquarters in central Johannesburg, live television pictures showed.
The hearing is a gamble for Mr Zuma. Mr Malema helped him rise to power but has in recent months been courted by Mr Zuma's rivals and is seen as a potential future leader. If he is exonerated, Mr Zuma could be fighting for his political life.
If found guilty of sowing discord in party ranks by the hearing - Mr Malema's second disciplinary hearing in just over a year - the firebrand youth leader could be suspended from the party for several years.
This would silence his calls for nationalisation of the mining sector, to the relief of investors, but would anger thousands of his supporters.
Police erected razorwire barricades around the ANC building while a police helicopter hovered overhead, a Reuters Television journalist said.
At least one police officer was wounded after being hit with a brick, a police spokesman said. South Africa's eNEWS channels said one of its television crews was also attacked.
The protesters were trying to break through the police barricades towards the building where the hearing was due to have started at 0800 GMT.
They waved placards saying: "Hands off Julius Malema" and one reading: "We are prepared to take arms and kill for Malema".
Although Mr Malema called for restraint from supporters yesterday, analysts said the violence could be orchestrated.
"If anyone thinks what is happening on the streets of Johannesburg is spontaneous combustion, well that is just rubbish," said Nic Borain, an independent political analyst.
"Malema is prepared to gamble everything on making his disciplining and removal from the party as costly as possible."
The hearing is as risky for Mr Zuma, who hopes to be re-elected ANC leader at a party meeting in December 2012, as it is for Mr Malema, who party insiders say ultimately wants the country's top job.
Mr Zuma is on a state visit to Norway this week.
The disciplinary panel is led by senior ANC member Derek Hanekom and includes mines minister Susan Shabangu, who has criticised Mr Malema's calls for nationalisation.
Mr Malema (30) and the top five members of the youth wing have been charged with sowing division in the party that has ruled South Africa since apartheid ended in 1994.
The charges also include bringing the ANC into disrepute by calling for an overthrow of the elected government in neighbouring Botswana.
On the eve of today's hearing, a defiant Mr Malema told reporters the League's push to nationalise mines could not be suppressed by his removal.
"This does not delay our economic struggle. We see this as a setback for the revolution we are pursuing. We will continue to push for economic freedom in our lifetime."