BOGOTA Colombia's ELN rebels released three oil contractors hours after kidnapping them in the eastern province of Arauca on Friday, a police commander said, following an intensive air and ground search launched by security forces.
The contractors, all from Colombia, had been hauled from their car by men in military fatigues commonly used by the country's guerrillas, near the town of Arauquita close to the eastern border with Venezuela.
The kidnapping followed a spate of bomb attacks in the past 10 days that shut some of the Colombian oil industry's biggest oil and gas pipelines. The sector has enjoyed an influx of foreign investment because of improved security in the past decade.
"It appears to be another doing of the ELN as part of its escalation in terrorist activities," Arauca regional police commander Wilson Bravo said on local television, which reported that the kidnapped contractors were a geologist, an assistant and their driver.
Bravo later told Reuters the men had been released, and attributed it to the pressure the kidnappers faced after security forces quickly launched a search.
Local media said the contractors work on Colombia's second-biggest oil pipeline, the Cano Limon-Covenas, owned by Colombian state oil company Ecopetrol and U.S.-based Occidental Petroleum Corp. It transports crude along the border with Venezuela to Colombia's Caribbean coast.
The 480-mile (780-km), 80,000 barrel-per-day pipeline, has been functioning sporadically since three bomb attacks closed it this month. The attacks were attributed to leftist guerrillas.
The ELN, or National Liberation Army, which operates mostly in the country's northeast, is the smaller of Colombia's two guerrilla groups, with about 3,000 fighters. The FARC, or Revolutionary Armed Forces of Colombia, has about 8,000 fighters.
Both groups have been fighting the government in a bloody five-decade conflict estimated to have killed more than 200,000 people.
In August, the ELN released a Canadian geologist it had held hostage for seven months. President Juan Manuel Santos had said the release was a condition for ELN peace talks with the government, which the rebel group has expressed interest in pursuing.
Both guerrilla groups have attacked oil infrastructure with increasing frequency in the past year or two, even with peace talks proceeding between the government and FARC. Oil companies had to contend with attacks as frequent as every two to three days in 2012.
The ELN has battled a dozen governments since it was founded in 1964 and is considered a terrorist group by the United States and the European Union.
It has sought peace before, holding talks with the Colombian government in Cuba and Venezuela from 2002 to 2007.
(Reporting by Luis Jaime Acosta; Writing by Julia Symmes Cobb; Editing by Peter Murphy and Peter Cooney)