Protest at Malaysia security law
Thousands of people have demonstrated in the Malaysian capital, Kuala Lumpur, against a controversial, decades-old law allowing detention without trial.
Police used tear gas and water cannons to disperse the protesters as they blocked several main roads for hours.
More than 200 arrests were made during the unauthorised march, attended by opposition leader Anwar Ibrahim.
Prime Minister Najib Razak said he had already agreed to review the controversial Internal Security Act.
The protest started after prayers finished at the national mosque, when a crowd of about 1,000 marched along one of the city's main streets.
A second crowd of several thousand came from the opposite direction.
The protesters had planned to march to the national palace to submit a petition to the king denouncing the security law.
Reports said there were up to 15,000 demonstrators facing 5,000 police.
Mr Anwar, who in the past has been imprisoned under the law, told the rally: "We gather today to fight a cruel law under a cruel administration."
Such a public gathering is rare in Malaysia where permits are needed for meetings involving four or more people, reports the BBC's Robin Brant in Kuala Lumpur.
Malaysia has been through a year of political turbulence as liberals and Islamists try to wrest power from the long-ruling UMNO Malay nationalist party.