Malaysians voted on Sunday in their first election in history with a change of government at stake, as a decades-old regime battles to hold off a rising opposition pledging sweeping reform.
Voting got under way at 8:00am (0000 GMT) as more than 8,000 polling centres nationwide opened with tensions high after a bitter campaign in the multi-ethnic country marked by opposition charges of election fraud and widespread violence.
The ruling bloc dominated by the United Malays National Organisation (UMNO) is one of the world's longest-serving governments, its supremacy never threatened since independence in 1957.
But the opposition captained by charismatic former UMNO star Anwar Ibrahim stunned the country by making unprecedented gains in 2008 polls and Sunday's vote has been keenly awaited since then.
Prime Minister Najib Razak's coalition had been expected to edge Anwar's three-party Pakatan Rakyat (People's Pact) alliance on Sunday.
But recent opinion surveys have indicated the race was too close to predict, and Anwar has been feted by festival crowds in the tens of thousands on the stump.
"There is clearly, undeniably, a major groundswell and a major shift among the population across ethnic lines," Anwar said after he cast his ballot in a polling centre in his northern constituency of Permatang Pauh.
Pakatan has capitalised on anger over corruption, authoritarianism, which it vows to end, and controversial affirmative-action policies for majority ethnic Malays, which Anwar says are abused to prop up a rich Malay elite.
Pakatan promises an end to UMNO's racial politics and has reached out to minorities and a younger generation exposed to alternative views found online.
His back to the wall, Najib has offered limited political reforms, but otherwise a largely stay-the-course vision for the Muslim-majority nation.
The opposition has set the stage for a possibly disputed result with numerous accusations of electoral fraud by Najib's coalition, known as the Barisan Nasional (National Front).
They include an alleged scheme to fly tens of thousands of "dubious" and possibly foreign voters to key constituencies to sway results.
A government official has said the flights were part of a voter-turnout drive. Najib, 59, has not commented.
It also emerged last week that indelible ink applied to voters' fingers to prevent multiple voting -- touted by Najib as a safeguard against fraud -- was easily washed off.
Emerging from Anwar's polling centre, Saad Adam, 76, complained to others waiting to vote that the ink came right off.
"They said it would last two to three days. But when I washed my hands to go to prayers, it just disappeared," he said, looking angry.
Anwar was a former deputy premier until his ouster in a 1998 power struggle and six-year jailing on sex charges widely viewed as trumped up. He later brought his star power to the once-weak opposition, dramatically changing its fortunes.
It remains to be seen whether Malaysians will vote out the only government they have known, and Najib has played on fears for stability while pledging to maintain solid economic growth.
His ethnic Malay-dominated regime retains powerful advantages, including control of traditional media and an electoral landscape critics say is biased.
Campaigning has been marred by hundreds of reports of violence, intimidation, arson and two small explosions, although no deaths have been reported.
Polling stations close at 5:00 pm (0900 GMT) with results expected to begin rolling out within hours.
"It's a tight run. But I'm not scared, I'm excited," said retiree H.Y. Ong, as he waited to vote in the capital Kuala Lumpur.
"The times have changed, they (the government) need to change. Money politics should be controlled," he added, while not divulging his voting preference.