Bogota, Colombia ? After a bloody campaign in which dozens of candidates were killed, Colombians elected state and municipal leaders Sunday, with a former communist union leader winning the mayor’s seat in Bogota.

The election was a day after voters rejected most points of a referendum championed by hard-line President Alvaro Uribe, according to results released Sunday. Uribe said the referendum would give him the necessary tools to fight terrorism and corruption and boost the faltering economy.

The referendum was the greatest defeat to hit Uribe since he was elected to office by a landslide last year on pledges to put this violence-wracked nation in order and clamp down on corruption.

The campaign period before Sunday’s vote was particularly violent, even by Colombian standards. Armed groups killed at least 30 candidates for mayor and kidnapped a dozen others.

Most of the attacks were carried out by leftist rebels, who sought to undermine Uribe’s contention he was bringing state control into the farthest reaches of the country, which has been racked by four decades of civil war that kills about 3,500 people, mostly civilians, annually.

The rebels’ archenemies, outlawed paramilitary groups, also intimidated candidates in order to have their favorites run unchallenged.

A glum Uribe appeared in Bogota’s main plaza alongside gun-toting soldiers in a pouring rain Sunday afternoon to vote in the mayoral and state elections. He declined to comment on the referendum results.

However, Defense Minister Martha Lucia Ramirez acknowledged defeat.

“All Colombians have lost an opportunity to adopt structural reforms,” she said.

Under heavy security, voters wait for the rain to stop at the entrance of a polling station in Bogota's main square. Voters on Sunday chose governors for Colombia's 32 provinces and more than 1,000 town mayors.