At least six soldiers died in an explosives attack perpetrated by suspected drug traffickers in northeastern Colombia, the army said on Wednesday. Another five soldiers were injured and one remains missing after the attack blamed on the Clan del Golfo cartel, the most powerful in the country but whose leader Dario Antonio Usuga was captured in October. “Unfortunately the murder of six of our soldiers is confirmed,” said the army in a statement. The five injured soldiers from the Fourth Brigade “were evacuated by airplane” to a hospital. “Troops on the ground are continuing to look for one of our soldiers,” added the army. The attack took place around midnight Tuesday in the Antioquia department. General Juvenal Diaz told Blu Radio that the Clan del Golfo was responsible for detonating “an improvised explosive device” as a military vehicle was passing. Antioquia is a key corridor for the transport of cocaine to Colombia’s Pacific coast and on to Panama. Colombia is the world’s largest producer of cocaine, much of which is smuggled into the United States and Europe. The Clan del Golfo has increased its attacks on the armed forces since the detention of Usuga, who is known by the alias Otoniel. Colombia’s government has approved the extradition of Usuga to the United States to face charges of drug trafficking. Before his capture, the Clan del Golfo used to export 300 of the 1,010 tons of cocaine that leaves Colombia every year, according to authorities.