Seven peacekeepers from Niger were killed Friday in an ambush in southwestern Ivory Coast, and more may be in danger, U.N. Secretary-General Ban Ki-moon said. The blue-helmeted peacekeepers were part of the U.N. Operation in Cote d'Ivoire on patrol near the border with Liberia, where threats of attacks against civilians have prompted the operation to strengthen its presence, the United Nations said in a statement. "These brave soldiers have died in the service of peace," Ban said. "I condemn this attack in the strongest possible terms." The incident occurred near Para Village, a spokesperson for Ban said in a statement quoted by CNN. Ban called on the government of Ivory Coast "to do its utmost to identify the perpetrators and hold them accountable." He added that he understood that other peacekeepers remained in danger. "Even tonight, after the attack, more than 40 peacekeepers remain with the villagers in this remote region to protect them from this armed group," he said. A spokeswoman for the U.N. mission in Ivory Coast said Friday's incident was the first attack on peacekeepers since they entered the country in 2004.