(CNN) -- At least six Italian peacekeepers and two civilians were wounded on Friday after an explosion targeted a convoy of the U.N. Interim Force in Lebanon, a U.N. spokesman said.
A UNIFIL logistics convoy had been headed along the main highway near Saida when the explosion occurred. Italy's Defense Ministry said the peacekeepers are among the 1,780 Italian soldiers who have been deployed in Lebanon since 2006.
Of the six, one was seriously injured, U.N. peacekeeping spokesman Nick Birnback said.
Birnback called the act "despicable" and announced the bolstering of security measures. The attack was meant to undermine U.N. efforts to foster stability in southern Lebanon, he said.
"It is important that the perpetrators of this attack are identified and brought to justice. UNIFIL's forensics and investigation teams are at the location and are working in close cooperation with their counterparts in the Lebanese army to determine all the facts and circumstances surrounding the incident," Birnback said.
Italian Foreign Minister Franco Frattini said he hoped the injured would recover quickly.
"I have learned the dramatic news from Lebanon, which cause me great grief and feelings of deepest condolences," he said.
Gerard Araud, France's ambassador to the United Nations and the presiding security council president, said on Friday night: "The members of the U.N. Security Council condemn in the strongest terms this terrorist attack (and) condemn all attempts to threaten the stability and security of Lebanon."
U.N. Secretary-General Ban Ki-moon noted that the attack came on the International Day of United Nations Peacekeepers. He said the United Nations will work with Lebanon to investigate.
UNIFIL was created by the U.N. Security Council in March 1978 "to confirm Israeli withdrawal from Lebanon, restore international peace and security, and assist the Lebanese government in restoring its effective authority in the area."
After the 2006 war between Israel and Hezbollah in Lebanon, the council "enhanced the force" and decided to "monitor the cessation of hostilities (and) accompany and support the Lebanese armed forces as they deploy throughout the south of Lebanon."
It also helps ensure "humanitarian access to civilian populations and the voluntary and safe return of displaced persons."
Ban cited the dangers and difficulties of peacekeeping.
"I pay tribute to the 120,000 United Nations military, police, civilians who are working under the blue flag around the world for the cause of peace."
CNN's Richard Roth, Hada Messia, and Nada Husseini contributed to this report