Liberian Information Minister Lewis Brown said the president had ordered the immediate deployment of the armed forces to the border in the wake of Friday's attack near the Ivorian town of Tai, which also left at least eight civilians dead and sent hundreds of people fleeing the area.
Human Rights Watch has said that militants have staged several cross-border attacks from Liberia, leaving at least 40 people dead in the last year. The violence has been blamed on mercenaries and militiamen who fought for ex-Ivorian President Laurent Gbagbo and then fled across the porous border into Liberia's forests, following his arrest last year.
In a report released Wednesday, the human rights group had accused the Liberian government of failing to respond to the presence of armed groups on the border, or to the recruitment of child soldiers.
Liberian Defense Minister Brownie Samukai said efforts were being made to prevent the use of Liberia's territory as a launching ground for attacks. "We all are surprised by the deterioration of the situation in Tai," said Samukai, adding that it was difficult to yet establish the nationalities of those involved.
Ivory Coast was brought to the brink of civil war when Gbagbo refused to cede power after losing a November 2010 election. The United Nations estimates at least 3,000 people were killed in the six months of violence that followed, and more than 60,000 Ivorian refugees remain in neighboring Liberia.
Gbagbo was arrested with the help of U.N. and French forces in April 2011, and is now facing charges of war crimes at The Hague. Friday's attack marked an unprecedented assault on U.N. peacekeepers, who have been in the country since 2004.
"This is the first time we have ever had such a type of attack in Ivory Coast. It's a very tough time for the whole mission here right now," said Sylvie van den Wildenberg, acting spokeswoman for the U.N. mission in Ivory Coast.
An Ivorian Cabinet official who was briefed on the matter said President Alassane Ouattara requested helicopter gunships from the U.N. and expected them to arrive by Monday. The official spoke on condition of anonymity due to the sensitivity of the matter.
Ivory Coast's deputy defense minister Paul Koffi Koffi said government forces, along with Liberian and U.N. forces, will launch an operation on June 15 to find the men responsible, whom he described as "militiamen or mercenaries."
Koffi Koffi said they could not respond sooner because it would take time to gather equipment and prepare the forces.
U.N. Secretary-General Ban Ki-moon condemned the attack "in the strongest possible terms," saying he was "saddened and outraged" about the deaths of the peacekeepers, all from Niger. He urged the Ivory Coast government to identify the perpetrators and bring them to justice.
Bert Koenders, the U.N. envoy to the West African nation, said the peacekeepers were part of a patrol south of the town of Tai, an area the U.N. mission recently reinforced because of threats of attacks against the civilian population. The ambush involved a large group of armed men, a U.N. official said, speaking on condition of anonymity because he was not authorized to speak publicly.
"Their colleagues are still in danger," Ban told reporters. "Even tonight, after the attack, more than 40 peacekeepers remain with the villagers in this remote region to protect them from this armed group."
Van den Wildenberg said several vehicles were on a reconnaissance patrol near the village of Para on the southern axis of Tai to follow up on "rumors of movement of armed people in the area and threats on the security of civilians."
"There were several vehicles on the patrol and the leading vehicles were strongly hit," van den Wildenberg said. "The area is densely forested and very tough terrain."
Western Ivory Coast has remained particularly unstable following Gbagbo's arrest, and Human Rights Watch said earlier this week that armed groups in Liberia who supported Gbagbo have killed at least 40 civilians in cross-border raids into Ivory Coast since July. The deaths have all been near Tai, Human Rights Watch said.
"In the four cross-border attacks since June 2011, the motivation appears to have been both political vengeance and related to land conflict - issues that overlap in Ivory Coast's volatile west. Those killed or whose houses were burned predominantly belong to ethnic groups that largely voted for president Ouattara," the group said in its report.
Matt Wells, West Africa researcher at Human Rights Watch, told the AP that the organization hasn't confirmed details of the attack but "pro-Gbagbo militants have conducted repeated raids from Liberia into this region of Ivory Coast."
"The Gbagbo camp often resorted to inciting rhetoric against U.N. personnel during the Ivorian crisis, though today's deadly attack is the first of its kind during the recent Ivorian crisis," Wells said.
"Liberian and Ivorian authorities need to quickly work together to bring to account those involved in this heinous act," he said.
At the end of April, the U.N. said there were about 9,400 peacekeeping troops, 200 military observers and 1,350 international police in the mission along with civilian staff. Over 40 countries are contributing military personnel.
