BOGOTA—Pumping on Colombia’s southern Transandino pipeline was halted on Jan. 14 after a bomb attack by the ELN rebels spilled crude into a river, state-run oil company Ecopetrol and the military said.

The National Liberation Army (ELN) is in the midst of a renewed offensive against the military and oil infrastructure, after the end of a months-long ceasefire amid peace talks to end more than 53 years of war.

The attack, which occurred late on Jan. 13 in Mallama municipality in Narino province, has not affected exports or crude production at fields in the southern jungle zone along the border with Ecuador, Ecopetrol said.

The 109-mile Transandino has the capacity to transport 85,000 barrels of crude per day.

The ELN, which has some 2,000 fighters, has killed two police officers and one soldier in attacks since the ceasefire ended on Jan. 9. The group on Jan. 13 kidnapped an Ecopetrol contractor repairing damage to the Cano-Limon pipeline, also bombed by the ELN, the army said.

President Juan Manuel Santos has recalled the head of the government’s negotiating team at the peace talks in Quito back to Bogota to discuss the future of talks.