(CNN) -- 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.
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More may be in danger, U.N. secretary-general says
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The peacekeepers were on patrol near the border with Liberia
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"We never had such an attack," a mission spokeswoman says
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U.N. peacekeepers have been in Ivory Coast since 2004
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Van den Wildenberg said she had received reports that some @placeholder citizens may also have been killed or wounded, "but we are still checking the facts."
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In the statement, Ban's spokesperson said the secretary-general "remains seriously concerned about the continued instability in the border areas between @placeholder and Liberia since the Ivorian post-elections crisis, which has resulted in the death of a number of individuals in that region."