ELN guerrillas killed ten soldiers in the deadliest rebel attack in Colombia so far this year, underlining the ELN's growing strength, which has been fuelled by increased involvement in the drug trade.
Fighters from the National Liberation Army (ELN) ambushed an army patrol near the Venezuelan border in the department of Norte de Santander.
The rebels launched an assault with gas cylinder bombs and homemade mortars, killing ten and wounding 11 more. The guerrillas also abducted one of the soldiers and seized rifles, grenades and a machine gun, reported El Pais.
There were no reported ELN casualties.
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Although the explosives used in the attack were homemade, the ambush displayed levels of sophistication and effectiveness that suggest the ELN is ramping up its operational capacities.
In 2006, the ELN was on the ropes, squeezed by a war with their larger cousins the Revolutionary Armed Forces of Colombia (FARC), still suffering from offensives launched by the paramilitary United Self Defence Forces of Colombia and under pressure from the army. The recovery that has allowed them to gather enough strength to mount the sort of attacks witnessed in Norte de Santander is in part rooted in the guerrillas' increasing role in the drug trade and alliances with the narco-paramilitary groups known as the BACRIM (from "bandas criminals" in Spanish or "criminal bands).
The region where the ambush took place is an ELN stronghold and the center for much of its drug trade activities. In Norte de Santander, the rebels are believed to control coca cultivations and cocaine laboratories and there is evidence they work closely with the FARC.
It is also likely the assault is part of the ELN's plans to force its way to the negotiating table with the Colombian government. While the government has been holding official peace talks with the FARC since October last year, the ELN has been sidelined despite repeated calls to be allowed to join and recent rumors that talks were imminent.
During this time, the ELN has repeated tactics used by themselves and the FARC to try and force the government into talks, staging several high profile kidnappings and announced a military campaign against the country's vulnerable underbelly -- the oil and mining industries that bring in the foreign capital feeding Colombia's economic growth.