On 51st Anniversary of FARC Rebellion, Peace Negotiator Confirmed Killed in Airstrike

Wednesday marked 51 years to the day since the Revolutionary Armed Forces of Colombia formed, a guerrilla army that at its height controlled nearly 30 percent of the country's territory.

Weakened today, and at the table with the government to end the hemisphere's longest-running armed conflict, the FARC marked its anniversary with the confirmation that one of its senior members and peace negotiators was killed in the government airstrike last week that left 27 rebels dead.

The rebel group said that Pedro Nel Daza Martinez, known by the alias Jairo Martinez, was on an educational mission in Gaupi, Cauca department, when Colombian forces attacked from the air.

Martinez was called one of the last the ideological leaders of the FARC's southern bloc. He was a veteran of peace negotiations under President Andres Pastrana between 1998 and 2002, which failed to end Colombia's war.

Jairo Martinez was also believed to have orchestrated kidnappings for the FARC.

The rebels on Wednesday also confirmed the death of Alfredo Alarcon Machado, aka Roman Ruiz, commander of the FARC's 18th Front, in an airstrike in the Pacific department of Choco. The government of President Juan Manuel Santos has escalated strikes against the rebels since a FARC raid in April killed 11 soldiers.

"The Santos government is mistaken if they think that with the mangled bodies and blood of our comrades, they will impose a justice system that does not pursue the responsibility of the powerful," Pastor Alape, a leading FARC negotiator, said upon confirming Jairo Martinez's death.

Related: Colombia Conflict Escalates, Worrying a Nation Watching Delicate Peace Talks

At least 220,000 people have died in Colombia and 5.7 million have been displaced as a result of the conflict, which began in 1964. A wide majority of those victims have been civilians.

Martínez was at the negotiating table in Havana until just some weeks ago, reports said, when he left to assist a program to rid Colombia of land mines left behind by the FARC.

The military however was suspicious of Martinez's presence in Guapi, claiming the program to de-mine had not been rolled out there.

"There are no humanitarian operations for the issue of de-mining in place where last week's bombing took place," said Deputy Defense Minister Jorge Enrique Bedoya, responding to questions in Colombia's Congress.

Related: Colombia's FARC Guerrilla Suspends Unilateral Ceasefire After 26 Killed in Military Airstrike