BANGKOK — Soon after coming to power four months ago, Najib Razak, the Malaysian prime minister, vowed to temper the country’s repressive laws and respect civil liberties though they have often been ignored.
But Malaysia’s honeymoon of liberalism hit the rocks over the weekend, when the police broke up a large rally in Kuala Lumpur, arresting nearly 600 people and reaffirming the governing party’s longstanding policy of zero tolerance toward street protests.
Opposition parties, which organized the rally, were calling for the repeal of a law that allows the government to jail its critics indefinitely without charge. The opposition is also pressing the government to expand an inquiry into the recent death under mysterious circumstances of a political aide after a late-night interrogation by anticorruption officials.
News services estimated that the rally on Saturday, which was broken up by thousands of police officers using tear gas and water cannons, drew about 20,000 protesters, making it the largest demonstration in two years.
“We can provide them stadiums where they can shout themselves hoarse till dawn, but don’t cause disturbance in the streets,” Mr. Najib said Sunday, according to the Malaysian news media.
Since taking office in April, Mr. Najib has gained favor with investors and businesspeople by partly dismantling a system of racial preferences that long caused resentment among the country’s minorities.
He also released 13 political detainees held without trial. An opinion poll conducted from June 19 to July 1 showed 65 percent of respondents were satisfied or very satisfied with his performance. The poll, by the Merdeka Center for Opinion Research, surveyed 1,060 voters.
More recently, Mr. Najib’s government has been criticized as reverting to the authoritarian tactics of previous administrations.
A former health minister and stalwart of the governing coalition, Chua Jui Meng, defected to the opposition in July, saying that Mr. Najib represented an “iron fist behind the velvet glove.”
Lim Kit Siang, a prominent opposition politician, said in a blog entry on Sunday that the large number of people detained “underlines” that the “greatest violators of human rights are often the police and the law enforcement agencies.”
The death of the political aide, Teoh Beng Hock, in July has galvanized opposition parties and caused widespread outrage, especially among the minority Chinese.
Mr. Teoh, a legislative aide in the opposition-controlled state of Selangor, was found dead beneath the 14th-story window of the offices of the country’s anticorruption commission after a nightlong interrogation. A pathologist’s report said he died of internal injuries from a fall.
A government minister initially said Mr. Teoh, 30, committed suicide, but his belt and back pockets were torn, adding to speculation that he might have been forced out the window.
After initial resistance, the government bowed to public pressure and ordered an inquiry into Mr. Teoh’s death as well as the interrogation tactics of the anticorruption officers.
Deaths in police custody have increased in recent years, according to Suaram, a human rights group. According to the Malaysian Home Ministry, 1,535 people died in police custody between 2003 and 2007, the latest year for which data is available.
