Anti-government protesters braved the threat of arrest

After warning women and children to get off the streets, police called in the water cannons, spraying the crowd with a mix of water and stinging pepper, a chemical irritant.

Some of the demonstrators later regrouped, and there were violent scenes as police - some plain clothed, others in balaclavas - arrested people in the crowd, including several women.

One report said some of the detainees were carrying shopping bags, and it was unclear whether they were passers-by or had intended to join the demonstration.

Anwar was sacked as finance minister in September

It is the second demonstration in two days to be broken up by police - on Friday they used teargas to disperse a few hundred supporters of Mr Anwar.

Mr Anwar was sacked by the Prime Minister, Dr Mahathir Mohamad, last month and later arrested under the Internal Security Act.

He is due to go on trial on November the second on 10 counts of corruption and sodomy - charges he denies.

Uncompromising approach

Prime Minister Mahathir has defended Mr Anwar's arrest

The BBC's correspondent in the region, David Willis says the authorities are growing increasingly uncompromising in their approach to street demonstrations - but there are still those who are determined to defy them.

The Malaysian authorities have declared illegal all demonstrations in support of Mr Anwar, and several people have been arrested in a series of anti-government rallies. They were later released on bail, pending trial.

This week, however, police warned that those who join the illegal protests could face arrest under the country's tough Internal Security Act, which allows for indefinite detainment without trial.

Call for observers

Earlier on Saturday, Mr Anwar's wife called for foreign observers to be allowed to attend the trial.

Mr Anwar's wife, Wan Azizah - called for observers

Wan Azizah Ismail said she was concerned about reported remarks by Dr Mahathir that observers would not be permitted in court because it would put pressure on the judges.

Speaking after an adjourned habeas corpus application, she said this gave the impression that the government alone was empowered to decide who attended the trial: "Is this an indirect way of influencing the courts by the executive?"

"I am of the opinion that we should show the world that the judiciary in Malaysia is independent," Mrs Wan Azizah said.

Some foreign observers have expressed interest in attending the trial amid allegations that Anwar was beaten while in police custody.