JAKARTA - AN INDONESIAN court sentenced the leader of a hardline Islamic group to 18 months in prison on Thursday for inciting violence at an interfaith rally in which dozens of people were injured.

Rizieq Shihab, leader of the Islamic Defenders' Front, or FPI, which is famous for smashing up bars and nightclubs during the Muslim fasting month of Ramadan, is an outspoken critic of Ahmadiyya, an Islamic sect that some Muslims consider heretical.

Thousands of Indonesians, including politicians, artists and religious leaders, gathered in central Jakarta in June to urge tolerance for Ahmadiyya, but the rally turned violent when Rizieq's supporters used poles to beat up women and the elderly, while the police did little to prevent the attacks.

'Defendant Rizieq Shihab has been proven beyond reasonable doubt guilty of inciting others to commit violence,' judge Panusunan Harahap told a central Jakarta court amid tight security.

Around 85 per cent of Indonesians are Muslim and most are moderate, but with elections due next year, the government is facing increasing pressure from the Islamic parties and from a small but vocal minority of hardline groups.

Outside the court, police used tear gas as an angry crowd of FPI supporters tried to touch Rizieq following his sentencing. Some supporters carried sticks and threw plastic bottles at the police.

'I don't like my teacher being jailed for one-and-a-half years,' said one man in the crowd who, like many of the FPI's supporters, was dressed in white robes.

Rizieq, who denied he is guilty, said he would appeal the sentence and continue his campaign to get the government to ban the Ahmadiyya sect. -- REUTERS