Colombia's Marxist FARC rebels said on Monday the end to their unilateral ceasefire, which was called off last week after a government attack killed dozens of guerrilla fighters, is a setback for peace talks to end five decades of war.
Speaking from Havana, Cuba, where talks have been taking place for two and a half years, the leadership of the Revolutionary Armed Forces of Colombia, or FARC, said peace would be unattainable if offensives intensify.
"Without a doubt the tragic events of last week are a step back," rebel negotiator Pablo Catatumbo said in a statement. "This is the wrong path and it is obvious peace will never be reached by escalating the conflict."
"We'll proceed with cool heads and ardent hearts, we cannot throw away our determined efforts in nearly three years of talks," Catatumbo added.
The FARC suspended an almost five-month unilateral ceasefire on Friday after troops killed 26 of its fighters, a move that looks set to ratchet up tension at the talks.
The government had briefly suspended bombing raids on rebel encampments but restarted them after the FARC killed 11 soldiers in restive Cauca province in April, effectively breaking the ceasefire.
The FARC, in the statement, repeated its demand for a bilateral ceasefire, which President Juan Manuel Santos has ruled out until a final peace deal is signed.
The first casualties of the renewed rebel offensive came on Sunday, when one policeman was killed and two were injured by a rebel bomb. A further eight FARC fighters were killed by government air raids.
Negotiators at the talks, championed by Santos, have reached partial accords on three of five agenda points: land reform, political participation for ex-rebels and an end to the illegal drugs trade.
Still under discussion are the thorny topics of victim reparations and FARC demobilization. The war has killed more than 220,000 and displaced millions since it began in 1964.