BOGOTA (Reuters) - A bomb attack by Colombia’s leftist ELN rebel group has halted pumping operations along the country’s second-largest oil pipeline, the Cano-Limon Covenas, sources from the military and state oil company Ecopetrol said on Monday.

The attack took place in rural El Carmen municipality in Norte de Santander province, near the border with Venezuela, the sources said. The bombing caused a crude spillage into a nearby river.

The sources spoke on condition of anonymity because an official announcement has not yet been made.

Production at the Cano Limon oilfield, operated by U.S.-based Occidental Petroleum Corp, and exports have not been affected, the sources said.

Ecopetrol officials said a team from the company was in the area to carry out clean-up operations. Repairs are expected to take several days, they said.

Attacks against the pipeline have left 751 victims over the last 17 years, including 167 deaths. Since 1986 the pipeline has been out of service 3,800 days, or 10.4 years, 30 percent of its life. Some 66 million gallons of crude have been spilled since 2000, according to Ecopetrol figures.

The 485-mile (780-km) pipeline can carry up to 210,000 barrels per day.

The National Liberation Army (ELN), considered a terrorist group by the United States and European Union, has frequently attacked Colombia’s oil infrastructure during the group’s five-decade war with the government.

Despite peace talks begun with the government in February, the ELN has continued pipeline attacks. It opposes the presence of multinational companies in the mining and oil sector, claiming that they seize natural resources without leaving benefits to the country’s population or economy.