Voting in national and local elections in the Philippines has been extended by one hour due to long queues of voters.
Filipinos will elect a new president and vice-president, as well as more than 17,000 other positions.
The queues have been linked to problems with new automated vote-counting machines, some of which had failed to operate properly in pre-poll testing.
Six people were killed as voters cast their ballots, amid reports of continuing violence in the south.
Benigno Aquino, the son of the popular former president, Cory Aquino, has been leading the polls but former president Joseph Estrada is also in the running.
Outgoing President Gloria Arroyo, whose term expires in June, is running for a seat in parliament.
Determined to vote
The BBC's Philippines correspondent Kate McGeown is at the Nemesio Yabut elementary school in the capital, Manila, and says long lines have formed with hundreds of people waiting in the heat for a chance to vote.
The school's principal, Marilyn Macalma, said she expected 22,500 people to turn up to vote there.
People take elections seriously in the Philippines and an estimated 85% of those eligible are expected to vote.
But as had been predicted, glitches have been reported with the country's new automated voting system.
Even the election front-runner, Mr Aquino, had trouble voting at his home province of Tarlac because the ballot-counting machine had broken down.
"Hopefully, this is just an isolated incident. We are waiting for more reports... (but) if people can't vote because the machines don't accept their ballots, then certainly that is a problem," Mr Aquino said.
Voter Armand Juele, 42, said he had queued for more than an hour to cast his ballot and the line was still 50m (yards) long.
"It's super-disorganised. There's no order. It's the worst election by far," he told Reuters.
Another unnamed voter said he had no intention of leaving despite the long queues.
"We have to push through with the voting. It would be a waste of our rights," he said.
Throughout the campaign the issue of the automated voting machines has dominated headlines.
Election commissioner Gregorio Larrazabal appealed to voters in Manila to wait patiently and said back-up machines were available if ones in use malfunctioned.
"What's important is that you will be processed. You will be able to vote. Your vote will be counted," he said.
The presidential contenders are vying to replace Mrs Arroyo, who came to power in 2001 and is stepping down as she reaches her constitutional two-term limit.
Her premiership has been marred by allegations of corruption and she has fended off several impeachment motions put forward by Congress.
She is now running for a post in Congress herself and her opponents have said they will file corruption charges against her once she no longer has presidential immunity.
Benigno "Noynoy" Aquino has been the pre-election day favourite to replace Mrs Arroyo.
Correspondents say the 50-year-old's political pedigree - as the son of the beloved former president who died in August last year - has been hugely important in his campaign, but he is also considered an honest, if inexperienced, candidate.
Joseph "Erap" Estrada is another front-runner but correspondents say his past could play against him. He was deposed and jailed by Mrs Arroyo in 2001 on allegations of corruption, although she later pardoned him.
Property tycoon Manny Villar is also expected to do well. His campaign on focused on what he portrays as his rise from poverty to riches but has been tainted by corruption allegations.
Security has been high around polling stations in an attempt to stave of the violence that has accompanied the country's past elections.
But there were sporadic reports of violence as polling took place.
- In southern Maguindanao province, two civilians were killed as private armies of rival vice mayoral candidates clashed in North Kabuntalan town, Lt Col Raymundo Ferrer told reporters
- Three people were shot dead and 10 others wounded in a pre-dawn clash clash between police and supporters of a mayoral candidate in the southern province of Zamboanga Sibugay.
- A cousin of the vice governor in North Cotabato province was shot dead while riding on a motorbike, local police said.
The latest deaths bring the toll over the four months leading up to the elections to 35 killed.
Those deaths are in addition to the 57 people killed in Maguindanao province in November when a group tried to register a candidate for the elections in an area held by a rival clan.
Twelve members of the clan, the Amapatuans, have been charged with involvement in the mass killing, but 10 of them are running for posts in these polls.