An address to parliament by South Africa's President Jacob Zuma has been halted by opposition MPs.
Mr Zuma was responding to allegations that he had "unduly benefitted" from an upgrade to his private home in Nkandla which cost taxpayers about $23m (£14m).
MPs from the new Economic Freedom Fighters (EFF) were not satisfied with his explanation and started chanting: "Pay back the money."
Parliament was suspended and security called to oust the EFF group.
Police entered parliament in Cape Town carrying riot shields, tear gas and batons but then aborted their plans to forcibly remove the EFF MPs.
The governing African National Congress (ANC) said it was "appalled" by the behaviour of the EFF parliamentarians.
The Democratic Alliance, the largest opposition party, said the EFF's "theatrics" meant South Africans "did not get answers from the president, to which they were rightfully entitled".
Analysis: Pumza Fihlani, BBC News, Johannesburg
South Africans may be divided over the behaviour of the EFF in parliament but its leader Julius Malema posed questions many here still want answered.
Nkandla remains a sore point for many citizens and the president has been accused of failing to account to the public that elected him into power.
So while they may not support the chanting and disruption to a formal sitting, many are quietly applauding their stand.
Mr Malema has never been one to shy away from confrontation; it was with tough talking that he defended President Jacob Zuma before their fall-out.
However uncomfortable to watch, many see this as South Africa's democracy at work.
It is not clear when the session will resume - possibly on Friday.
Many MPs were waiting to question the president when the session was suspended.
After being pressed by Mr Malema on when he would repay the Nkandla money, Mr Zuma said he had "responded appropriately to parliament" and said it was now in the hands of the government.
The EFF has 25 MPs in the 400-member parliament after gaining 6% of the national vote in May's election.
It was the first election contested by the EFF, led by controversial former youth leader Julius Malema.
He formed the EFF last year following his expulsion from the ANC in 2012.
A one-time ally of Mr Zuma, he had been sacked after the pair fell out, with Mr Malema calling for radical policies to ease poverty.
The EFF often wear red workers' overalls in parliament.