(CNN) -- A former leftist guerrilla has started his term as the mayor of Colombia's capital with a pledge to ban carrying weapons on the city's streets.
"More important than prohibiting people from drinking or dancing at night, or stores from opening, is prohibiting the instruments that allow people to kill other people. And of these instruments, in first place are firearms, which the law allows based on norms that I do not share, because we told Colombia in '89 that we put down our weapons," Gustavo Petro said at his inauguration in Bogota Sunday.
Petro is a former member of the M-19 leftist guerrilla group, which signed a demobilization agreement with the Colombian government in 1989.
On Sunday, Petro noted he could not go against national rules allowing gun ownership, but he said stopping people from carrying weapons would cut down on crime.
"I can assure you that it is one thing to own a weapon and another thing to carry it in the streets, in night clubs, in buses, on corners, in parks," he said. "I want the police force of this city to help me in this task, once the decree is issued, to measure statistically the level of crime in the city in a few months. Bogota will shout to the world that this is a space free of weapons."
A military tribunal jailed Petro in 1985 for his connections with the M-19 rebel group, which was known for high-profile attacks against Colombian authorities -- including a takeover of the nation's Palace of Justice that year, which left dozens dead, including 11 Supreme Court justices.
Speaking to a crowd of cheering supporters in October, Petro called his election to Bogota's top post a sign that voters were "saying yes to reconciliation."
He has said building homes for the needy and overhauling the education system will be among his top priorities.
Before his election as mayor, Petro, trained as an economist and business administrator, had served as a lawmaker, a diplomat and a presidential candidate.
In the political sphere, Petro quickly developing a reputation as a crusader against corruption.
As a senator, he led the charge against lawmakers and members of then-President Alvaro Uribe's government, accusing them of connections with paramilitary groups.
In 2010, he came in third place when he ran for president in Colombia.
Petro, 51, is not the first Latin American leader with a guerrilla warrior background. Voters in Uruguay and El Salvador also have elected politicians who were previously involved in rebel groups.
Journalist Fernando Ramos contributed to this report from Bogota, Colombia.