UNIFIL said a logistics convoy was targeted along the main highway near Sidon. The peace-keeping force said six officers were injured, one of them seriously.

Earlier reports said a UN officer was killed. UNIFIL, which denied casualties, said two Lebanese civilians were also injured, Middle East Newsline reported.

This marked the first major attack on UNIFIL in nearly three years. The 13,500-member force has long been on alert for attacks by the Iranian-sponsored Hizbullah and Al Qaida. The last lethal bombing of a UNIFIL patrol was in 2008.

Several contingents in UNIFIL have been examining the prospect of reducing or withdrawing from the mission. France and Italy have maintained the largest presence in the peace-keeping force, which in 2010 stopped patroling Shi'ite villages amid Hizbullah threats.

"In the aftermath of this attack UNIFIL's determination and commitment to our mandate is ever stronger," UNIFIL said. "We are continuing our operations in south Lebanon together with the Lebanese Armed Forces for the implementation of our mandate under resolution 1701. At the same time, the security of UNIFIL personnel is paramount and we have further strengthened our security measures."

---