Authorities in Colombia have launched a massive search and rescue mission for an army general who they suspect was taken captive by FARC rebels, prompting the government to suspend critical peace talks.

General Ruben Dario Alzate and two civilians were abducted on Sunday afternoon while travelling by motor boat along a remote river in western Colombia to survey an energy project.

Let it be clear to the entire country: when a kidnapping occurs the only ones responsible are the kidnappers, in this case the FARC terrorists.

Defence Minister Juan Carlos Pinzon

A fourth soldier managed to flee the ambush and reported that the captors were members of a FARC brigade.

FARC has not commented on the allegations. 

"Negotiations with FARC are suspended until the facts of the kidnapping of
general Alzate are clarified," Colombia's Ministry of Defence said in a tweet citing President Manuel Santos Santos, following a meeting between the president and military leaders.

"If confirmed, it would be the first time in a half-century of conflict that the rebels have taken an army general hostage, Colombian media reported.

It also comes as frustration with two-year-old peace talks between the rebels and the government is building due to an apparent refusal by the guerrilla fighters to wind down attacks in areas where they remain dominant.

Al Jazeera's Lucia Newman, reporting from Chile, said Santos was under huge pressure from "millions of Colombians hoping the negotiations would put an end to the longest-running internal conflict in the western Hemisphere."

"In the short term this is a really serious setback for peace talks which had been the cornerstone of Santos' administration," Newman said.

Civilian clothing

Newman said Alzate was dressed in civilian clothes when he was abducted, which was a breach of protocol.

"More importantly, it could mean that the FARC did not even know they were kidnapping a member of the military of that rank," she said.

Santos immediately ordered the top military commander and his defence minister to travel to the capital of Quibdo to oversee the rescue operation.

"Let it be clear to the entire country: when a kidnapping occurs the only ones responsible are the kidnappers, in this case the FARC terrorists,'' Defence Minister Juan Carlos Pinzon said late on Sunday night.

He added that the government had also contacted the International Red Cross to facilitate an eventual release of the hostages.

The US-educated Alzate took over as commander this year of the newly established Titan Task Force, a 2,500-man fighting force comprised of army and marine personnel sent to combat the rebels and drug-traffickers in the remote. water-logged jungles surrounding Quibdo.