A roadside bomb planted by leftist rebels killed 10 soldiers as they patrolled in southwestern Colombia on Thursday, the deadliest attack on security forces this year, authorities said. A similar attack killed nine police officers a day earlier.
The new attack, which also injured 13 soldiers, occurred shortly after midnight Thursday morning, said the commander of the army's 3rd Division, Gen. Hernando Perez Molina, who blamed Colombia's largest rebel group, the Revolutionary Armed Forces of Colombia, or FARC.
"We know this is the FARC because it fits their modus operandi, and historically they have operated in this zone," said Perez.
He said the patrol was searching for criminal gangs and far-right paramilitaries near the town of Tulua when the explosive was set off by remote control.
The area in Valle del Cauca province is home to some of Colombia's largest drug traffickers, as well as leftist rebels and far-right death squads. Both the security forces and the rebels have increased their presence in the zone in the past year.
The FARC, which partly funds itself through Colombia's massive cocaine industry, has been fighting for more than four decades against the government and far-right paramilitaries.
On Wednesday, nine police officers were killed when a roadside bomb planted by leftist rebels destroyed their passing truck in central Colombia. Officials also blamed the FARC for that attack.
The same day, 10 FARC fighters forced passengers off of two buses, then loaded explosives onto them near Sonson, 100 miles northwest of Bogota, the town's mayor said. There were no injuries, and the army was defusing the explosives Thursday.
Since a large-scale offensive by government security forces in 2002, the rebels have cut back on direct battles with the army, preferring attacks with land mines and bombs.