Two Colombian military intelligence chiefs were sacked Tuesday after the president ordered a probe of claims an army unit spied on his negotiators holding peace talks with FARC rebels.

Two Colombian military intelligence chiefs were sacked Tuesday after the president ordered a probe of claims an army unit spied on his negotiators holding peace talks with FARC rebels.

President Juan Manuel Santos called the alleged eavesdropping an attempt by "obscure forces" to sabotage his efforts to end the half century old insurgency, denouncing it as "totally unacceptable."

The alleged spying was first disclosed by the magazine Semana, which reported Tuesday that a special army unit was set up in 2012 to illegally intercept the communications of members of the government's negotiating team.

The Bogota's delegation to the peace talks in the Cuban capital Havana is led by former vice president Humberto de la Calle, Sergio Jaramillo and Alejandro Eder.

Santos said the state had an obligation to spy on enemies like the FARC, or organized crime.

In 2011, Santos disbanded an intelligence agency, the Administrative Department of Security, which was involved in the alleged illegal wiretapping of leftist politicians and was said to have links to right-wing paramilitary groups.

Since November 2012, his government has been in negotiations with the FARC, the country's largest and longest-fighting insurgency. It has been at arms since 1964.