Protestors clashed with police at the third Bersih rally in Kuala Lumpur on Saturday, after protestors among the crowd broke through barriers, entering the city's historic Merdeka Square.
Authorities had taken action before the event, sealing off a square in the capital and serving a court order banning the protest. Police used tear gas and water cannon to break up the rally, as they had done last year at a similar demonstration.
Police estimated that at least 30 000 people participated in the rally, while independent Malaysian media put the number at more than twice that. They said that 471 people were arrested during the demonstration for free and fair elections, although they were freed the following day after. Security forces would decide whether to file charges against the demonstrators later, National Police Spokesman Ramli Yoosuf told journalists.
Earlier on Saturday, the crowds were vocal but peaceful. The main actions of the protestors were over when a crowd tried to break through barriers in Merdeka Square.
The rally poses a dilemma for Najib, who since last year's crackdown has sought to present himself as a reformer, launching a campaign to repeal laws previously perceived as authoritarian.
Commentators have said the risk of political backlash after the rally may delay a poll which had been due to take place as early as June.
ISEAS Deputy Director, Ooi Kee Beng, has said that the end of Najib's premiership has been somewhat mixed, with his reforms not going far enough, coming too late, and without the apparent support of key members of his coalition.
Despite this, Malaysian opposition groups have failed to win over voters either. Many supported Bersih, and hope that an increase in political engagement will swing votes their way. Though Saturday's police crackdown may play into the hands of Bersih organisers and opposition parties, violence may also play into the hands of the authorities, who have accused the organisers of inciting trouble.
Bersih 2.0 in July 2011 was previously a "watershed" moment for Najib, prompting him to promise reform of an electoral system that the opposition said favoured the long ruling National Front coalition.
The government has said it has met or is addressing seven of Bersih's eight main proposals for the election. Bersih says the proposals do not meet most of its key demands, including the lengthening of the campaign period to at least 21 days from seven days, and installing international observers at police stations.
The coalition is demanding elections be postponed until full reforms are implemented.
Report: Malaysian police, protesters clash, raising poll doubts (Reuters, 28 April 2012)
Report: Malaysia police free all 471 vote reform activists (AFP, 29 April 2012)
Report: Malaysian police fire teargas, water cannons at protesters (CNA, 28 April 2012)
Commentary: A General Over a Hesitant Army (TODAY, 30 April 2012)