BOGOTA, Colombia -- Gunmen killed Archbishop Isaias Duarte Cancino of the city of Cali on Saturday, silencing a voice that had often been critical of leftist Colombian rebels.

The gray-haired bespectacled archbishop had just completed a group wedding when he was shot outside the church in Cali, witnesses said. No one immediately claimed responsibility for the attack.

Duarte was dead on arrival at Carlos Holmes Trujillo Hospital, said hospital director Ricardo Vanegas. TV footage showed people weeping outside the hospital in Cali, Colombia's third-largest city.

Edilberto Ceballos, Duarte's driver, told Caracol radio network that the archbishop was shot several times, including in the head.

"Two guys came and opened fire and hit him three or four times, maybe even six times," the driver said. "I saw him dead."

Duarte had frequently criticized leftist rebels for their attacks and kidnappings. Colombia's 38-year-old civil war has intensified since peace talks with the main rebel army, the Revolutionary Armed Forces of Colombia, or FARC, collapsed on Feb. 20.

A smaller rebel group, the National Liberation Army, known as the ELN, had also earned Duarte's ire for conducting mass kidnappings in Cali in recent years, including abducting worshippers at a Cali church. Although talks with the FARC collapsed, the ELN is participating in peace talks with Colombian government representatives in Havana, Cuba.

Alvaro Uribe, who is leading the polls ahead of presidential elections next May 26, said he was saddened by the assassination.