Four men who identified themselves as members of the National Liberation Army (ELN) abducted two people from a vehicle near Teorama in the department of Norte de Santander on Monday, a spokesman for Colombia's elite Guala anti-kidnapping police told AFP.

Later, a former mayoral candidate from Teorama and another man who tried to mediate their release, were also taken hostage.

The captors carried heavy weapons and "identified themselves as members of the ELN," the spokesman said.

Authorities say the kidnappings are part of a fight between the ELN and remnants of a Maoist guerrilla group known as the Popular Liberation Army (EPL), a group the Colombian government says is really a criminal gang known as Los Pelusos.

The conflict is over drug trafficking routes, as Norte de Santander is a major coca-producing region near the Venezuelan border.

Peace talks between the government of President Juan Manuel Santos and the ELN leadership resumed in the Ecuadoran capital Quito last month.

But clashes between ELN and the alleged EPL members have left at least six people dead and caused some 2,500 to flee their homes, according to UN Office for the Coordination of Humanitarian Affairs (OCHA).

The number of kidnappings in the area have spiked as a result of the clashes, local official Nelson Arevalo said.

"There is a considerably higher number of kidnappings that are not reported because of family members' fears," Arevalo told local Blu Radio.