The Democratic Republic of Congo closed its border with Zambia, the main export route for the country’s copper, after clashes between residents and security forces in which at least three people died. One person was killed in the violence at Kasumbalesa border post that began Thursday night, according to Eric Monga, a spokesman for the chamber of mines in the southeastern Haut Katanga province. Two people died in the protests that followed the killing of a money changer by criminals late Thursday, government spokesman Lambert Mende said by phone from Kinshasa. The local residents were protesting what they said was “a failure of the police to protect the population,” Mende said. Congo is Africa’s biggest copper producer and the world’s largest source of cobalt. The Central African nation produced 489,207 metric tons of copper and 29,152 tons of cobalt in the first six months of this year. Monga, who is also the managing director of logistics company Trade Service, said a police station was burned down and vehicles are being held at a separate customs point 12 kilometers (7.5 miles) north of the border.