Davao City Mayor Rodrigo Duterte is taking a strong lead in the Philippine presidential election, according to an unofficial and partial tally of votes cast on Monday evening.

Based on 60.02 percent of registered voters' ballots, Duterte had 10,459,816 votes, followed by Grace Poe at 5,952,327 votes and Manuel Roxas at 5,806,579, the statistics from partial and unofficial Comelec Transparency serve showed.

Comelec, the Commission on Elections, is the Philippine principal government agency tasked by the Constitution to enforce and administer all laws and regulations concerning the conduct of regular and special election.

The results does not include overseas and local absentee voting.

Five candidates contested in the election for the presidency to succeed Benigno Aquino III, whose six-year term ends on June 30.

Rodrigo Duterte, mayor of the south Philippine city of Davao, has been leading most of the opinion polls since April.

Some 33 percent of the voters said they would vote for Duterte in the final pre-election survey conducted by Social Weather Station. The country's renowned polling body carried out the survey from May 1 to 3 through face-to-face interviews with 4,500 validated voters nationwide with a sampling error margin of 1 point.

The 71-year-old mayor is known to have made Davao one of the safest cities in the Philippines through tough regulations and iron-fist approach in crime fighting.

During the presidential campaign period, he vowed to wipe out corruption, drugs and criminality in three to six months if he wins the election.

His aggressive behavior and offensive language won him a lot of supporters, but aroused concerns and controversy as well.