The Colombian army says it has killed the top FARC rebel leader Alfonso Cano in combat.
The government, backed by the US, has been fighting the leftist Revolutionary Armed Forces of Colombia since 2002.
Several FARC commanders have been killed in recent years.
This latest killing shows how the Colombian army can strike at the group, even deep in the jungles where they have their bases.
Once a powerful force controlling large areas of Colombia, it is thought the organisation is at its weakest in decades.
President Juan Manuel Santos has kept up the pressure since he came to office last year.
Bombings and kidnappings by FARC have been significantly reduced.