HAVANA (Reuters) - Colombia's Marxist-led FARC guerrillas warned on Tuesday that escalating violence could damage peace talks in Cuba, where the government and insurgents are seeking a negotiated end to half a century of civil war.
"It's time to stop the war in order not to harm the peace process and avoid useless casualties," rebel leader Ivan Marquez said in Havana.
"We ask President (Juan Manuel) Santos to once again consider the possibility of stopping the war with a cessation of hostilities," he said.
Latin America's longest-running guerrilla war has killed some 220,000 people and displaced millions more. After a partial respite earlier this year, combat has raged anew.
In March, Santos agreed to halt aerial bombing in recognition of a unilateral cease-fire called by the Revolutionary Armed Forces of Colombia (FARC) at Christmastime. But he ordered new air assaults in response to a rebel attack that killed 10 soldiers in April.
Since then both sides have carried out attacks, with the FARC formally renewing offensive operations and sabotaging roads, pipelines and utilities.
On Monday, four soldiers were killed in northeastern Colombia when a helicopter dropping off troops was destroyed by explosives detonated remotely by the FARC, the army said.
Since starting talks in November 2012, government and rebel negotiators have reached partial accords on three of five agenda points: land reform, the political future of the FARC and an end to the illegal drugs trade. Still under discussion are victim reparations and the FARC's demobilization.
Should the two sides reach a comprehensive agreement, it would be submitted to voters for ratification.
Reporting by Nelson Acosta; Editing by Daniel Trotta and Tom Brown