BOGOTA, Colombia (AP) — A spate of attacks against civilians and military bases in Colombia’s southwestern region has raised security concerns as the country heads to a May presidential election in which crime is expected to be one of the top voter concerns.

Rebel groups have staged 26 attacks with explosives and drones since Friday, including a deadly blast Saturday on a highway between the cities of Cali and Popayan, according to Colombia’s defense ministry. The death toll in that explosion rose to 21 people on Monday.

Violence in the region is nothing new. Illegal groups have sought to control the area for decades, deeming it strategic for illicit activities, such as illegal mining and drug trafficking, including the cultivation of coca leaf, the raw material for cocaine.

Authorities blamed a group known as the FARC-EMC for the lethal explosion, near a tunnel on the Pan-American Highway. The group is led by Nestor Vera — commonly known as Iván Mordisco — a former member of the Revolutionary Armed Forces of Colombia, known by its Spanish acronym FARC, who refused to join a 2016 peace deal with the nation’s government.

Sergio Guzmán, a political risk analyst in Colombia’s capital, Bogota, said that Mordisco’s group could be trying to demonstrate that it has the capabilities to do serious damage, and is seeking to “establish its credibility” with Colombia’s next government as it positions itself for future negotiations.

“Part of what they are doing is establishing leverage towards the future,” Guzmán said.

Under President Gustavo Petro, a former member of a guerrilla group, the Colombian government has attempted to stage peace talks with the nation’s remaining rebel groups through a strategy known as ” total peace.”

The government has offered ceasefires to various groups in an effort to promote peace negotiations, but analysts say the strategy has failed, because these groups used the ceasefires to regroup, rearm and strengthen their grip over communities.

Groups like the FARC-EMC have been known to tax residents in areas under their control, and also forcibly recruit youth into their ranks.

“The government’s peace policy has been naïve,” said Javier Garay, a political science professor at Colombia’s Externado University. “They thought that if they had a condescending attitude towards these groups they would receive a positive response.”

In late 2023, the FARC-EMC entered peace talks with the Colombian government. But a faction led by Mordisco abandoned the talks in April 2024, and has been fighting the Colombian government since then.

Elizabeth Dickinson, a Colombia analyst at the International Crisis Group, said that Mordisco’s group is particularly strong in the provinces of Cauca and Valle del Cauca, where it’s fighting for control of drug trafficking routes and illegal gold mines.

For the past two years, Mordisco’s group has also used drone attacks and car bombs, to respond to an offensive from the Colombian military in the Micay Canyon, a remote area covered with coca fields that is under the FARC-EMC’s grip.

Dickinson said that the latest attacks in southwest Colombia are one way for the group to show that it can sustain its “asymmetrical war” against the government.

Colombia’s defense minister on Sunday said that kidnappings and lockdowns enforced by rebel groups on communities had decreased in Cauca over the past year because of the government’s actions.

But the government’s total peace strategy has come under fire from the opposition, whose candidates are hoping to benefit from the nation’s security woes, as they promise to take a tougher stance on crime.

Petro is barred by Colombia’s constitution from running for another term. But his party’s candidate, Iván Cepeda, has promised to continue peace talks with rebel groups.

Cepeda said on X that he rejected the recent attacks in southwest Colombia, and urged authorities to investigate whether they were part of an effort to interfere with the election.

“It is worrying that these terrorist actions are happening in a region where there is ample support for our political project,” Cepeda said.

Voters in Colombia will head to the polls on May 31 to choose from 14 different presidential candidates, including Cepeda, and conservatives Abelardo de la Espriella and Paloma Valencia.

While Cepeda favors the continuation of Petro’s “total peace” strategy, his conservative rivals have said that they favor confronting rebel groups and putting more military pressure on them before resuming peace talks.

Guzmán said that while this weekend’s attacks “deepen the discomfort” with the security situation in Colombia — where a presidential candidate was killed last year — both sides will try to profit from this new wave of violence.

“Government supporters will use the attacks as an opportunity to say that that this is exactly why we need to reach urgent agreements with (rebel) groups,” Guzmán said. “Detractors will say this is why we need to more aggressively attack them.”

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