Colombia's leftist FARC guerrillas blew up a portion of the main road linking their country with neighboring Ecuador, authorities said Tuesday.

The explosives were apparently hidden in a sewer pipe, Temistocles Ortega, governor of the southwestern province of Cauca, told Blu Radio, as was the case in an April 1 FARC attack at another point of the Panamericana highway.

"This is a modus operandi that wasn't known before," he said.

"If it's a tactic going forward, it's impossible to exercise control over the great number of sewer pipes on all the roads of Colombia," Ortega said.

The crater caused by the explosion rendered a stretch of the Panamericana between the towns of Mojarras and El Bordo impassible for trucks and buses.

Authorities were working to repair the damage amid increased traffic as many Colombians take to the roads for Holy Week vacations.

A recent spate of attacks by the Revolutionary Armed Forces of Colombia, or FARC, in the southwestern part of the country has created a "worrisome situation," Gov. Ortega said, describing the rebels' approach as "clumsy."

The FARC's April 1 strike on another link of the Panamericana highway blasted a hole 10 meters (33 ft.) wide.

Representatives of the FARC and the Colombian government have been engaged in peace talks since November 2012. EFE