BOGOTA (Reuters) - Colombian leftist Gustavo Petro came top during the first round of the Andean country's presidential election on Sunday and will face a surprise contender - businessman Rodolfo Hernandez - in a second round in June.

       Petro, a former member of the M-19 guerrilla movement who has vowed profound economic and social change, took 40.4% of votes, national registry office tallies showed, while Hernandez, who made late gains against predicted second round candidate Federico Gutierrez, won 27.9%.

       A second round of voting will take place on June 19.

       (Reporting by Julia Symmes Cobb; editing by Grant McCool)