A Venezuelan soldier was killed and another wounded in a clash with an armed group in the latest incident along the country's volatile frontier with Colombia, the army said on Wednesday. The incident on Tuesday in western Tachira state was the most serious violence along the border since five Venezuelan troops and a state oil company engineer were killed in an ambush in September, According to Reuters. "At the moment of the attack, troops from the Second Theater of Operations repelled the aggression by opening fire," regional commander Gen. Isbeli Delgado said in a statement. The military did not say whether they believed armed Colombian groups were involved in the attack. Officials said only that nine people had been arrested. Relations between Venezuela and Colombia have been strained repeatedly by security incidents along their 1,400-mile (2,200 km) border, which runs through barren flatlands, mountains and dense jungle. Kidnapping, drug smuggling and spillover from Colombia's four-decade-old war involving leftist rebels and right-wing paramilitaries are common. --More 2347 Local Time 2047 GMT