The soldier serving with the UN Interim Force in Lebanon (UNIFIL) was killed and at least one other wounded gravely in the blast as they patrolled the coastal city of Sidon, ANSA reported.
"In principle we have one fallen and one gravely injured," said an Italian defence ministry spokesman contacted by AFP in Rome.
A UNIFIL spokesman in Beirut said six soldiers were wounded -- one seriously -- along with two civilians in the explosion, for which no group claimed immediately responsibility.
"According to our preliminary report, late this afternoon there was an explosion targeting a UN Interim Force in Lebanon logistics convoy along the main highway near Sidon," spokesman Neeraj Singh told AFP.
UNIFIL was set up in 1978 to monitor Lebanon`s border with Israel and expanded after a 2006 war between the Jewish state and the Lebanese Shiite militant group Hezbollah.
The multinational force currently has 13,000 troops stationed in south Lebanon, with Italy holding the largest contingent.
UNIFIL has been the target of three unclaimed attacks, the latest in January 2008 when two Irish officers were wounded by a roadside bomb.
In the deadliest incident, three Spanish and three Colombian peacekeepers were killed in June of 2007 when a booby-trapped car exploded as their patrol vehicle drove by. (*)