Malaysian Prime Minister Abdullah Ahmad Badawi defended a decision to detain five ethnic Indian activists under a tough security law as in the interests of public order, state media reported.
The five leaders of the Hindu Rights Action Force (Hindraf), pushing for an end to alleged discrimination of ethnic Indians in multi-racial Malaysia, were picked up on Thursday and held under the Internal Security Act (ISA).
The controversial law allows for indefinite detention without trial.
"Our action is justified. We have to take action if something undesirable to national security and public safety happens," he was quoted as saying by the official Bernama news agency late Thursday.
"I am duty-bound to act because the people want the government to take action. The people don't want to see this country in chaos," he said.
Abdullah, who is also the minister responsible for internal security, said national security concerns overrode freedom of expression.
"Between the freedom of expression and public safety, I will give importance to public safety. If you want to speak up, you must follow procedures," he said.
"This is not a nation that shuts the mouth of everyone. The people are not dumb. If we want freedom, we must be responsible. Freedom cannot be given without responsibility."
Opposition parties and human rights groups, who have campaigned for the abolishment of the ISA, slammed the government's actions and the United States has also called for the five detainees to be provided with fair treatment.
According to rights group the Voice of the Malaysian People (Suaram), the latest arrests take the number of people detained under ISA to 89. Almost half of those held are alleged Islamic militants.
Hindraf enraged the government last month by mounting a mass rally alleging discrimination in Malaysia, which is dominated by Muslim Malays.
Police used tear gas, water cannons and baton charges to break up the street protest, which drew 8,000 people and came just two weeks after another rare demonstration organised by electoral reform campaigners.