Colombian President Juan Manuel Santos on Friday urged the Revolutionary Armed Forces of Colombia (FARC) guerrillas to "set a deadline" for the peace process that was initiated two years ago.

The president said the government is losing its patience after FARC rebels killed 11 defenseless soldiers Wednesday.

"FARC gentlemen, listen to the national outcry. Do not be deaf to what Colombians are shouting to you. It's time to end the war," Santos said at the presidential palace.

"We are running out of patience. We have to set a deadline for this process. Your willingness for peace must be proven by facts and not just words," he said.

The president made the statement during a speech at the end of the welcoming ceremony for South Korean President Park Geun-hye, who began her official visit to Colombia on Friday.

The rebel guerrillas on Wednesday ambushed a group of about 30 soldiers who were resting in a rural area in the southwestern Cauca Department, and attacked them using gunfire and explosives. Besides the 11 deaths, 17 were injured.

Peace talks between the Colombian government and the FARC, the largest guerrilla insurgency in the country, have been going on in the Cuban capital of Havana since November 2012, with the aim of ending the five-decade conflict.