The smaller of Colombia's two main guerrilla groups said Monday that a Canadian mining engineer abducted last month will remain a captive.

About 25 members of the National Liberation Army, or ELN, stormed the Snow Mine camp in the northern province of Bolivar and took six people prisoner, including the Canadian and two Peruvian nationals.

The ELN handed over the other five hostages to the International Red Cross last Friday.

Jernoc Wobert, a 47-year-old engineer, remains in the custody of the guerrillas.

He is a vice president of Geo Explorer, a subcontractor of Canada's Braeval Mining Corporation, which operates the Snow Mine project.

The ELN linked its decision to hold onto Wobert to unhappiness over the presence of foreign mining companies in Colombia.

"The mining concessions ... originally were granted to the communities of traditional miners who live there, but due to maneuvers of corrupt intermediaries, those concessions ended up in the hands of the Canadian firm, based in Toronto, which hired engineer Wobert and sent him to Colombia," the ELN said in a statement dated Feb. 15.

Colombian military officials estimate the ELN has some 1,500 combatants. EFE