Hardline anti-crime candidate Rodrigo "Digong" Duterte has claimed victory in the Philippines presidential election.
The official PPCRV poll monitor said the mayor of the southern city of Davao had more than 14.8 million votes - about 39 percent - with 90 percent of ballots counted.
Manuel Roxas is in second place with nine million (23 percent). The winner is decided on a simple majority of votes cast.
Mr Duterte has been the long-time front-runner in a campaign also driven by the economy and corruption.
President Benigno "Noynoy" Aquino is standing down because the constitution limits presidents to one six-year term. Filipinos are also picking a vice-president and local officials.
The PPCRV (Parish Pastoral Council for Responsible Voting) is accredited by the election commission to monitor counting but its reporting does not represent an official tally.
But with his lead appearing unassailable, Mr Duterte told AFP news agency: "It's with humility, extreme humility, that I accept this, the mandate of the people".
He said his law and order policy had been the key to his success.
"What I can promise you is that I will do my very best not just in my waking hours but even in my sleep," he said.
Mr Duterte has made many controversial statements during his campaign, saying that he would butcher criminals.
"Forget the laws on human rights. If I make it to the presidential palace, I will do just what I did as mayor. You drug pushers, hold-up men and do-nothings, you better go out. Because I'd kill you," he said at his final campaign rally in Manila on Saturday.
"I'll dump all of you into Manila Bay, and fatten all the fish there," he added.
A former state prosecutor nicknamed "The Punisher", he has been mayor of Davao for more than 22 years.
When he took office, the city was plagued by violence, due in part to a communist insurgency in the region. The local authorities began arming civilian militias to tackle to communist insurgents, and those militias turned into death squads which targeted anyone seen as a threat to public order.
Under his stewardship, the city also built a large integrated emergency response centre and its crime statistics have fallen.
He recently joked that, as mayor, he should have been first to rape an Australian missionary murdered in a prison riot, but he later apologised.
"They raped all of the women... There was this Australian lay minister... when they took them out... I saw her face and I thought, 'Son of a bitch. What a pity... they raped her, they all lined up. I was mad she was raped but she was so beautiful. I thought, the mayor should have been first."
Mr Duterte initially said his comment was simply "how men talk" but later issued an apology, saying: "There was no intention of disrespecting our women and those who have been victims of this horrible crime."
His tough approach has earned him the nicknames "The Punisher" and "Duterte Harry".
During a televised presidential debate, he said he would kill his own children if they took drugs.
'Duterte has a mandate'
The election campaign has also focused on reforming the economy, infrastructure, and on the territorial disputes with China in the South China Sea.
Manuel Roxas is a former investment banker and the grandson of the first president of the Philippine Republic.
Senator Grace Poe, a former school teacher and first-term senator, is currently third with about 21 percent.
She has admitted defeat.
"I respect the results. Duterte has a mandate. Let's give him a chance," she said.
President Benigno Aquino had been leading attempts to bring together other candidates in an effort to defeat Mr Duterte.
He warned that if Mr Duterte were to be elected, it could mean a return to dictatorship.
A vice-president, senators and about 18,000 local officials, including mayors, are also being elected.
Among the candidates for the vice-presidency is Ferdinand "Bongbong" Marcos Jr, the son of late dictator Ferdinand Marcos.
He had been leading the count for much of the day but was overhauled by Maria Leonor Robredo. Nevertheless, the count is extremely close.
With 90 percent of votes counted, she has 34.89 percent to Mr Marcos's 34.82 percent, a gap of fewer than 30,000 ballots in more than 35 million cast.
More than 54 million people were registered to vote across the archipelago of 7000 islands.
Voting had been extended for an hour in some areas after glitches with vote-counting machines.
More than 100,000 police officers were on duty amid violence ahead of the election.