South Africa's governing ANC has dismissed a request by controversial Youth League leader Julius Malema to drop his disciplinary case.Mr Malema, 30, is accused of "sowing divisions" in the party and bringing it into disrepute by calling for Botswana's government to be overthrown.Once a close ally of President Jacob Zuma, the populist Mr Malema has become a fierce critic.The case is being seen as a test of Mr Zuma's leadership of the party.Thousands of his supporters clashed with police as the hearing began on Tuesday. Some burned T-shirts bearing Mr Zuma's face.But the ANC dismissed all 22 arguments presented by Mr Malema's lawyers and the hearing now resumes on Monday, 5 September.The BBC's Karen Allen says security is extremely tight outside the ANC headquarters, where Mr Malema's supporters have gathered.She says they remained defiant as the ruling was announced and continued to call for change in the party's leadership.