Malaysian police detained more than 440 people and sealed off parts of the capital on Saturday in a bid to stop thousands of anti-government protesters from putting on a massive show of strength against Prime Minister Najib Razak.
Thousands of police, some in trucks mounted with water cannons, fanned out across the city of 1.6 million people and set up roadblocks to stop the protest, which, if successful, could derail Najib's economic reforms program.
A big turnout could signal that the ruling National Front coalition was losing ground, possibly making Najib reconsider a snap election and delaying painful economic reforms seen as essential to woo substantial foreign investment.
Polls are not due until 2013 but analysts have said Najib is likely to seek an early mandate after economic growth accelerated to a 10-year high in 2010.
The Bersih, or Clean, group has vowed to bring together tens of thousands of supporters in the city's downtown area to demand electoral reforms, in what could be the biggest anti-government demonstration since Anwar Ibrahim's sacking as deputy premier in 1998 led to violent street rallies.
"We want to send a very clear message that we don't want a fraudulent electoral process," Anwar, who now heads a three-party opposition coalition, told Reuters at a hotel near the downtown area.
Accompanied by his wife and a daughter and dressed in a yellow T-shirt, the color of the protest movement, he said he would join the demonstration later. "We are not sure whether we will get to our destination. But the show must go on," he said.
The protesters had gathered around the city center to march to a stadium in the downtown area despite police warnings that what they were doing is illegal.
"I am hoping we will make it through the police blocks," said Nor Shahidal, a college student in her early 20s, as she made her way to the national mosque.
"We are not being disruptive, we want to walk for free and fair elections."
Police said more than 441 people were taken into custody by mid-day. The rally organizers said they were determined to carry on with the protest.
"We are fighting for free and fair elections," Ambiga Sreenevasan, head of Bersih coalition, told reporters.
"The government uses might, we use our right. Our right will eventually prevail."
Taxi and bus services into the city center were halted on Saturday, turning the usually busy tourist and shopping area in central Kuala Lumpur into a ghost town. Several roads were blocked off by police vehicles.
Most suburban train services were however functioning, and areas outside the city center were not much affected.
Major street demonstrations are rare in this Southeast Asian country, but the rise of alternative media channels and a signs of strength in the opposition are gradually creating a more vocal Malaysian public.
Tens of thousands of demonstrators took to the streets at a November 2007 rally, which analysts said galvanized support for the opposition ahead of record gains in a 2008 general election.
Najib took power in 2009, and inherited a divided ruling coalition which had been weakened by historic losses in the 2008 polls. He has promised to restructure government and economy and introduced an inclusive brand of politics aimed at uniting the country's different races.
Najib's approval ratings have risen from 45 percent to 69 percent in February, according to independent polling outfit Merdeka Center. But analysts said recent ethnic and religious differences have undermined his popularity.
