MESETAS — UN Secretary-General Antonio Guterres on Sunday praised the "total commitment" of Colombia’s government and former FARC rebels to peace-building, as the military blamed a smaller rebel group for bombing an oil pipeline.

"A peace-building process is not easy," Guterres said during a visit to an area where former fighters of the Marxist Revolutionary Armed Forces of Colombia (FARC) are being reintegrated in civilian life.

The government of President Juan Manuel Santos and the FARC signed a peace deal in November 2016 to end their half-century conflict. Some 260,000 people have died, 60,000 more are unaccounted for and seven million have been displaced since the insurgency began in 1964.

The UN is tasked with verifying compliance with the pact. Guterres heard complaints from the former rebels, now transformed into a political party, that it has not been properly implemented.

"There are imperfections, there are delays, but what was very clear to me is the total commitment of the government and the FARC to peace-building," said Guterres, who is Portuguese.

Before ending on Sunday a two-day visit to support the peace effort, he highlighted the "courage" of both sides to put an end the conflict.

Guterres met on Saturday with Santos, and heard from ex-rebel leaders about what they called the "disfigurement of the text and the spirit of the agreement" for peace.

In a report to the UN Security Council in December, Guterres said that a significant number of FARC rebels "have joined illegal or dissident groups" as a result of a "growing frustration with the lack of opportunities" in civilian life.

Additional strain has come over relations between the government and Colombia’s last rebel group, the National Liberation Army (ELN).

Santos on Wednesday suspended peace talks with the ELN in response to what he said were guerrilla attacks earlier that day, at the end of a 101-day ceasefire.

In the latest incident, on Saturday night, the army blamed ELN rebels for a bombing of an oil pipeline in Narino region on the Ecuador border.

Pumping was suspended on the Trans-Andean Pipeline linking Colombia and Ecuador but there were no injuries, an army statement said.

State oil company Ecopetrol said "the attack caused a leak of crude oil affecting the Guiza River," and warned residents not to consume the contaminated water.

On Saturday police said gunmen claiming to be from the ELN kidnapped a Colombian petroleum engineer near the Venezuelan frontier. — AFP