Filipinos are voting for a new president and other leaders, with outspoken mayor Rodrigo “Digong” Duterte the favorite to win.
Five candidates are running but Digong Duterte led polls ahead of voting, despite controversial comments while campaigning and a hard-line stance.
The campaign has been driven by public concerns about the economy, inequality and rampant corruption.
More than 100,000 police officers are on duty amid violence ahead of voting.
On May 9, seven people were shot dead in an ambush by unknown gunmen in the town of Rosario, in Cavite province, south of the capital, Manila.
The region had been considered an area of concern because of its political rivalries, said local media.
On May 8, a mayoral candidate was murdered in the south of the country.
President Benigno “Noynoy” Aquino is standing down as the constitution limits presidents to one six-year term. Filipinos will also pick a vice-president and local officials.
Rodrigo Duterte has run a campaign focused on law and order issues, but made many controversial statements, including saying that he would butcher criminals.
A former state prosecutor nicknamed “The Punisher”, Rodrigo Duterte has been mayor of the southern city of Davao for more than 22 years.
He recently joked that, as mayor, he should have been first to rape an Australian missionary murdered in a prison riot, but he later apologized.
Digong Duterte’s closest rivals in the opinion polls are Grace Poe – a former schoolteacher and first-term senator – and Mar Roxas, a former investment banker and the grandson of the first president of the Philippine Republic.
President Benigno Aquino has been leading attempts to bring together other candidates in an effort to defeat Rodrigo Duterte.
He warned that if Digong Duterte were to be elected, it could mean a return to dictatorship.
In a final rally on May 7, Benigno Aquino appealed to voters: “I need your help to stop the return of terror in our land. I cannot do it alone.”
However, the other four candidates – also including Jejomar Binay and Miriam Defensor-Santiago – refused to step aside.
A vice-president, senators and about 18,000 local officials including mayors will also be elected.
More than 54 million Filipinos are registered to vote across the archipelago of 7,000 islands.
Voting began at 06:00 local time and is due to end at 17:00.
Voting could be extended in some areas, because of problems with new electronic voting equipment, election officials said.