Suspected FARC guerrillas blew up a stretch of the Transandino oil pipeline over the weekend near Tumaco, a city on Colombia's Pacific coast, halting the flow of crude, officials said.

Revolutionary Armed Forces of Colombia, or FARC, fighters used dynamite to blow up the pipeline at kilometer 96 between the rural communities of La Guayacana and El Pailon, near Tumaco, Tumaco Mayor Victor Gallo told RCN Radio.

"Ecopetrol's contingency plan has been activated and we are activating the municipal plan to deal with the risk of pollution from the crude," the mayor said.

Ecopetrol operates the 306-kilometer (190-mile) Transandino pipeline, which links Ecuador's border region to the Colombian Pacific port of Tumaco.

The FARC has staged a series of attacks recently on infrastructure, targeting electricity transmission towers and leaving Tumaco without power for more than 10 days.

Two employees of utility company Centrales Electricas de Nariño, or Cedenar, and an Indian guide were killed last Thursday by landmines planted by the rebels near the toppled transmission towers.

The FARC has staged many attacks in recent years on energy infrastructure on the border with Venezuela and in the southwestern provinces of Nariño, where Tumaco is located, Cauca and Valle del Cauca.

The FARC, Colombia's oldest and largest leftist guerrilla group, is on both the U.S. and EU lists of terrorist groups. Drug trafficking, extortion and kidnapping-for-ransom are the FARC's main means of financing its operations.

The FARC has suffered a series of setbacks in recent years at the hands of the Colombian security forces.

Alfonso Cano, the FARC's top leader, was killed on Nov. 4 in a military and police operation that the government hailed as the biggest blow to the FARC in its nearly 50-year history.

Cano, a 63-year-old intellectual who had entered the ranks of the FARC 30 years ago, was killed in in a remote area of the southwestern province of Cauca a few hours after fleeing a bombardment.

The FARC also suffered a series of blows in 2008, with the biggest coming in July of that year, when the Colombian army rescued a group of high-profile rebel-held captives: former presidential candidate Ingrid Betancourt, U.S. military contractors Thomas Howes, Keith Stansell and Marc Gonsalves, and 11 other Colombian police officers and soldiers. EFE