Early results in the presidential election in Mexico suggest a comfortable win for opposition candidate Enrique Pena Nieto.
A win for him would see the return to power of the PRI (Institutional Revolutionary Party), which governed Mexico for 71 years until it was defeated in 2000.
Mr Pena Nieto, 45, is on some 38%, several points ahead of Andres Manuel Lopez Obrador, 58, who has not conceded, the BBC reports.
Outgoing president Felipe Calderon has congratulated Mr Pena Nieto and promised to work with him during the transition to his inauguration in December.
"I sincerely hope for the smooth running of the next government for the benefit of all Mexicans," Mr Calderon said in a televised address.
The election campaign has been dominated by the economy and the war on drugs and thousands of police were on duty for the vote on Sunday amid fears of intimidation from drug gangs.
More than 55,000 people have been killed in drug-related violence since Mr Calderon took power in 2006.
Mr Pena Nieto had been presented as the new face of the PRI - a break with the party's long and at times murky past that included links with drug gangs.
"There will be no pact nor truce with organised crime," Mr Pena Nieto said.
Mr Lopez Obrador running for the leftist Party of the Democratic Revolution (PRD) is in second place with about 31% of the vote and was the runner-up in the 2006 election, the BBC reports.
The official quick count, published by the electoral authorities, is based on returns from a sample of about 7500 polling stations throughout Mexico.
Voters are also choosing a new Congress of 500 deputies and 128 senators, and six state governors. Nearly 80 million people are eligible to vote.