Rioters thronged Johannesburg's city centre on Tuesday, hurling broken bricks at police and journalists and burning pictures of President Jacob Zuma, all in the name of ANCYL leader Julius Malema.

African National Congress Youth League supporters, waving placards bearing Malema's face next to the words, "Hands off our leaders", flooded the streets around the ruling party's headquarters, where youth leaders were facing a disciplinary hearing.

A policeman was hospitalised after suffering head injuries, at least five journalists were hit by rocks and the windows of an eNews satellite van were broken.

Malema warned his own supporters against attacking the media and the police.

"You cannot throw stones at journalists because journalists are just messengers... if you attack journalists, you will lose public sympathy," he told a crowd at Beyers Naude square, who were chanting "Juju! Juju!" and shouting, "the president!" and "the future of our country!".

"The police is not your enemy. These are the people employed to protect you," said Malema.

He said: "You must know who is the enemy", after which the crowd started chanting "Zuma! Zuma!".

Malema lectured his supporters that ANC alliance leaders needed to be respected, after a day of violent protests which saw the burning of t-shirts bearing Zuma's face and ANC flags.

"Don't burn the flag of the ANC. That is who we are... we cannot burn ourselves, especially the black, green and gold. You are here because you love the ANC. We must exercise restraint," he said.

Malema said the ANC "will always be there", but "individuals come and go".

Rubber bullets and teargas were fired several times during the day at Malema supporters, who broke off pieces of concrete barriers, cut through yellow tape used to close off streets and set dustbins alight.

Shops shut their doors after rioters banged on windows and threw pieces of glass at them, while several banks in the city closed early.

But ANC secretary general Gwede Mantashe said the ruling party, which had brought the charges against the youth league leadership, would not be bullied.

"We are not intimidated... they failed [in doing that]," Mantashe told reporters outside Luthuli House.

The disciplinary hearing against Malema and five others went ahead despite the violence, he said.

Malema, league spokesperson, Floyd Shivambu, league deputy president Ronald Lamola, secretary general Sindiso Magaqa, his deputy, Kenetswe Mosenogi and treasurer general Pule Mabe faced charges of bringing the ANC into disrepute and sowing divisions in ANC ranks.

This was after Malema said the ANCYL would send a team to Botswana to consolidate local opposition parties and help bring about regime change, as it believed the government there was "in full co-operation with imperialists" and was undermining the "African agenda".

Mantashe said the ANC would not take responsibility for the violence that happened while the disciplinary hearing was in progress.

"Whoever brought the crowd must take responsibility, whether it's an attack on the police or journalists or passing cars, the ANC will not take responsibility for that," Mantashe said.

Street blocks around Luthuli House had been closed to traffic from early morning, when the initial small group of supporters, who had held a night vigil for Malema, started growing in numbers.

Late morning school children arrived to join in the protests.

Police officers were continuously taunted, with Malema supporters shouting derogatory names at them, including "sex machine" or just repeatedly shouting "sex", referring to recent reports in the Sowetan newspaper of two police officers having sex while on duty.

The Umkhonto we Sizwe Military Veterans' Association called on the ANC to add more charges to the charge sheet against Malema and his five co-accused following the violence on Tuesday.

"What happened in the Johannesburg city centre was done in the youth league's name and they should take responsibility," said MKMVA spokesperson Ike Moroe.

The ANC's alliance partners, the SA Communist Party and the Congress of SA Trade Unions, also condemned the youth league supporters' behaviour.

The youth league itself issued a statement and attempted to distance itself from the events, which made news headlines world-wide, with Luthuli House and the ANC Youth League making the list "breaking globally" Twitter trends.

The league said it would never be associated with "unruly, disruptive elements and agents provocateurs".

The police insisted that the situation was under control, with the metro cops making one arrest and national police not securing any arrests.

"No-one was arrested," said Gauteng police spokesman Lt-Col Lungelo Dlamini. "There were stones thrown from the crowd but the police managed to maintain the situation.

"No serious crimes were committed," said Dlamini, who earlier confirmed that the injured police officer was hit on the head by a rock and hospitalised.