Colombian Rebels Gun Down 11 Soldiers and a Cop in an Ambush

Colombia's second-largest rebel group, the National Liberation Army, or ELN, has stepped up attacks against government forces in the midst of exploratory peace talks aimed at ending decades of conflict.

The group ambushed a patrol in the mountainous department of Boyacá on Monday morning killing 11 soldiers and a police officer, the government said.

Three soldiers were also injured and two were kidnapped by the rebels, according to a defense ministry statement that said two election officials and their indigenous guide were also missing after the attack. The ambush came a day after the ELN killed another soldier in the northwestern region Uraba, hundreds of miles away from Boyacá.

Though the ELN have regularly targeted infrastructure, attacks this bloody have become rare. Local media is giving Monday's ambush blanket coverage and calling it the deadliest ELN-related action in years.

President Juan Manuel Santos suggested that the group is seeking to strengthen its hand ahead of future peace talks, but insisted such a strategy would backfire.

"If the ELN think that these acts will win them political space or strengthen them in a future negotiations, they are completely wrong," the president told reporters on Monday evening. After meeting with military leaders on Tuesday Santos tweeted  "I ordered the intensification of operations against those who don't take the path of peace."

The Marxist ELN, currently estimated to have around 2,000 members, has been fighting the government since 1964. Colombia's biggest rebel force — the Revolutionary Armed Forces of Colombia, or FARC — has around 7,000 members. The FARC have been in peace talks with the government for three years, with a series of recent agreements reached in Cuba suggesting a final deal could be signed by April 2016.

Related: Colombian Government and Rebels Are Going to Help Search for People They Disappeared

The ELN have also been seeking a peace deal of their own. Exploratory talks about talks were announced in June last year with the process gathering momentum in recent months sponsored by the Ecuadoran government. Rafael Correa, President of Ecuador, said earlier this month that just "three percent" of the conditions required for formal negotiations to begin were still missing.

While the rebels have carried out attacks on military targets and infrastructure such as oil pipelines at the same time as they talk peace, they have appeared intent on limiting casualties. They were blamed by the government for two small bombings in Bogotá, the andean nation's capital, earlier this year, leaving ten injured.

Related: Related: Colombia Blames Twin Bombings in Bogota on ELN, Arrests 15

Monday's unusually bloody attack took place in the territory of the Uwa indigenous group that has long been an ELN stronghold and home to their most military powerful front, according to Adam Isacson, a Colombia expert at the Washington Office on Latin America (WOLA).

Isacson said that rather than a negotiating strategy, the attack could be a message from a faction within the rebel group's hierarchy opposed to peace talks. The ELN's commander in Boyacá, Gustavo Giraldo, known by the nom de guerre 'Pablito', is believed to be skeptical about negotiating with the government.

"Pablito could be sending a message to the rest of the ELN leadership about not rushing into talks," Isacson told VICE News.

The rebel group's radio station put out a communique stating that it had "no information" about the attack and calling on the government to agree to a bilateral ceasefire. "No more pain and death in the homes of guerrillas, soldiers and police officers," the statement read.

Despite Monday's setback, President Santos said he remained committed to a peaceful resolution to decades of war with the ELN. "The death of these members of the security forces should inspire us to continue looking for peace," he said in a statement on Monday evening.

Since 1964, more than 220,000 people have died in Colombia's war between the state, leftist rebels, right-wing paramilitaries, and the drug cartels. More than six million have been displaced. Most of the conflict's victims are civilians.

The Colombian government said the patrol ambushed on Monday was transporting votes from the previous day's gubernatorial and mayoral elections. Aside from the ELN attacks, the elections were unusually free of the violence that often marks election day in Colombia.

Related: Related: An Unexpected Wave of Low-Impact Bombings is Troubling Colombia's Capital

Follow Joe Parkin Daniels on Twitter: @joeparkdan