Opposition candidate Enrique Pena Nieto is set to become Mexico's next president, exit polls suggest.

Mr Pena Nieto secured about 40% of the vote, the polls say, comfortably beating his main rivals, BBC reports.

A win for the 45-year-old former state governor would see the return to power of the PRI, the party that ran Mexico for more than seven decades.

Thousands of police were on duty for the election, amid fears of intimidation from drug gangs.

Mexicans were also electing a new congress and some state governors.

Celebrations at the headquarters of the PRI (Institutional Revolutionary Party) started after the polls closed.

Party president Joaquin Coldwell said all the polls "irreversibly" showed Mr Pena Nieto would win the poll, which was dominated by the economy and the war on drugs.

Mr Pena Nieto has been presented as the new face of the PRI, a break with the party's long and at times murky past. The party held on to power for 71 years until it was defeated in 2000.