Colombia has announced the capture of a top commander of the main left-wing rebel group, the FARC.
Palmera is on FARC's 22-member general staff
Officials said Ricardo Palmera, better known as Simon Trinidad, was arrested at a clinic in Ecuador, in a joint operation with Colombia and the US.
Mr Palmera, the most senior FARC member to be captured, played a key role in failed talks with the Colombian Government in 2002.
Analysts say his arrest is a coup for Colombian President Alvaro Uribe.
Mr Uribe - a staunch US ally - has made the defeat of the rebels a cornerstone of his administration.
Battery of charges
Mr Palmera was captured by Colombian and Ecuadorean authorities on Friday while he was being treated at a clinic in the south of the Ecuadorean capital Quito, Colombian officials said.
FARC says it is fighting for socialist reforms
"We had been tracking him for months and he arrived at a health centre, apparently sick, and we captured
him," a Colombian police commander told Reuters news agency.
Mr Palmera was receiving treatment for a serious, perhaps terminal, illness, the BBC's Jeremy McDermott in Colombia reports.
He says Mr Palmera, unlike most FARC (Revolutionary Armed Forces of Colombia) guerrillas, comes from a wealthy family, and before he joined the rebels he was a bank manager.
Mr Palmera rapidly moved up the FARC ranks, becoming a member of the group's general staff.
The 22-member body is in charge of the 16,000-strong rebel army.
Mr Palmera is set to be flown from Ecuador to Colombia as soon as possible, where he faces a battery of charges, our correspondent says.
If convicted, he could be jailed for at least 30 years.
FARC and a smaller rebel group, ELN, right-wing paramilitaries and the government have been fighting each other for four decades in Colombia.
In the past decade alone, more than 35,000 people are believed to have been killed in the fighting.