Seven United Nations peacekeeper soldiers were killed yesterday when they were ambushed while on patrol in Ivory Coast.
The killings took place close to the Liberian border in an area that was recently reinforced by the UN to protect civilians. The seven dead troops were from Niger.
UN Secretary-General Ban Ki-moon said he was "outraged" by the killings and demanded that the attackers be brought to justice.
Peacekeeping troops were last night dug in close to the town of Tai in the south-west of the country in case of a further attack. Further reinforcements were expected to move in today.
Ivory Coast is recovering from the violence that followed the 2010 election when the president, Laurent Gbagbo, refused to accept that it had been won by Alssane Ouattara. He was eventiually ousted when France and the UN backed troops fighting for Mr Ouattara.
The identity of the attackers was unclear, but more than 40 civilians have been killed in cross-border attacks in the last year. They are thought to have been carried out by Liberian mercenaries and Ivorian fighters loyal to Mr Gbagbo.