From The Associated Press
By JULIA ZAPPEI – 3 hours ago

KUALA LUMPUR, Malaysia — Riot police charged demonstrators with batons and fired tear gas Saturday to disperse thousands of people marching in Malaysia’s largest city to protest a law that allows indefinite detention without trial.

People began massing at Kuala Lumpur’s main mosque, a shopping mall and a train station Saturday morning in defiance of government warnings that police would crack down on demonstrators, who are pushing leaders to scrap the Internal Security Act, which allows the imprisonment of people regarded as security threats. Police said many thousands had taken to the streets, with some news Web sites putting the count as high as 20,000.

Police fired tear gas and chemical-laced water to disperse the crowds shortly after they began marching toward the national palace. The protesters — who chanted “Reformasi,” the opposition’s slogan for political change — had planned to submit a petition to the country’s king, the constitutional monarch, to denounce the security act.

Witnesses said police wielding batons charged the protesters and scuffled with them. Many people ran into alleys and shops nearby to avoid being arrested.

“The police are really brutal,” opposition leader Anwar Ibrahim told reporters at the protest. “This clearly shows (the government’s) intolerance to any dissent. … We gather here today to fight a cruel law.”

Before the march started, Kuala Lumpur Police Chief Muhammad Sabtu Osman said 150 people — identified as protesters because they were wearing opposition T-shirts and headbands — had been detained to prevent them from taking part. Opposition activists estimated at least 200 people were detained by the time the protest ended.

Government authorities had warned they would not allow the protest, saying it could undermine public peace.

Authorities set up roadblocks across Kuala Lumpur to deter the demonstrators from trying to reach the city center, sparking massive traffic crawls. Hundreds of riot police backed by trucks mounted with water cannons stood outside train station and shopping mall where the demonstrators had arranged to gather.

Restaurants and stores were shuttered on several streets ahead of the rally — the biggest street protest in Kuala Lumpur since a November 2007 when tens of thousands of minority ethnic Indians demanded racial equality.

A police official at the scene, who spoke on condition of anonymity because he was not authorized to make public statements, said authorities could only estimate that there were “many thousands of protesters.”

The Star newspaper and Malaysiakini news Web site reported a total of 20,000 protesters in three different areas.

Prime Minister Najib Razak has promised to consider amending the security act, though government officials have repeatedly said it is necessary to safeguard national security, and on Friday he urged people not to join the protest.

Nazri Aziz, the Cabinet minister in charge of legal affairs, said Saturday that as long as the National Front ruling coalition “is leading the government, the ISA will not be abolished,” The Star reported on its Web site.

Human rights groups estimate at least 17 people are being held under the act, mainly for alleged links to militants and document forgery.

Activists have long decried the decades-old act, instituted during the British colonial era, saying it is sometimes used to jail government critics and dampen dissent.

Human rights activists have held numerous smaller rallies over the years to protest the security act, but Saturday’s protest received a boost after opposition parties urged their supporters to come out in force.

Associated Press writer Sean Yoong contributed to this report.