Former leftist guerrilla Gustavo Petro won the race for mayor of the Colombian capital, taking nearly 33 percent of the vote in a field of 11 candidates.

His closest rival, former Bogota Mayor Enrique Peñalosa, conceded late Sunday, a few hours after the polls closed in nationwide municipal and regional elections.

"I congratulate Gustavo Petro for his triumph. For the good of our city I wish him the best in his administration," said Peñalosa, who ran the city in 1998-2001.

Peñalosa started the campaign as the favorite and received public support from conservative former President Alvaro Uribe.

The 51-year-old Petro called his victory "humble" because "there are many challenges" for Bogota, a metropolis of more than 8 million people.

Speaking after his victory became official, the erstwhile senator committed himself to rigorously applying the Law of Victims and of Restitution of Lands in the Colombian capital, a measure intended to help peasants turned into refugees by the country's decades-long internal conflict.

"The violence has brought to Bogota more than 400,000 (displaced) people and the mayor of Bogota places himself in the first rank so that those people may enjoy the restitution of their lands, comprehensive reparations, because that is the basis of forgiveness. Forgiveness is the basis of reconciliation and reconciliation is the name of peace in Colombia," he said.

And he also said that his victory shows that Bogota had decided "to take in a son of the 1989 peace process," an allusion to the dissolution of the M-19 guerrilla group, which he joined in the 1980s.

"Bogota did not fall into the trap of the politics of hate and eternal war. Bogota is saying yes to reconciliation, yes to peace," he said in his message.

The Progressive Movement, created by Petro as a vehicle for his mayoral bid, is "the social force that will carry Bogota society to the complete fulfillment of the challenges of the 21st century," he insisted.

"One of the great consequences of today's result is that the (movement) will transform itself into a national movement to build a much more democratic Colombia," he said.

The movement was created last March after Petro abandoned the leftist PDA party.

Petro left the party after exposing corruption on the part of Bogota's incumbent PDA mayor, Samuel Moreno.

While serving in the Colombian senate, Petro uncovered evidence of extensive connections between public officials and right-wing militias. The ensuing "para-politica" scandal has led to dozens of prosecutions.