Mexican presidential candidates began campaigning Thursday for the July 2 election.
Candidates are competing to take over the presidency from Vicente Fox, who is limited by the constitution to one six-year term in office.
Leftist candidate Andres Manuel Lopez Obrador, a former mayor of Mexico City, had a lead over the other candidates in pre-campaign polls. He represents the Party of the Democratic Revolution.
He is followed by Felipe Calderon, of the president's conservative National Action Party.
Behind the two leading candidates is Roberto Madrazo, of the Institutional Revolutionary Party, or PRI, which ruled Mexico for most of the 20th century.
Campaign issues are expected to focus on bolstering the economy and slowing the loss of workers to higher-paying jobs in the United States.
Some information for this report provided by AP and Reuters.