A roadside bomb struck a UNIFIL vehicle near the southern Lebanon town of Tyre on Monday, security officials reported.
There were no immediate reports of injuries.
Lebanon's state-run National News Agency said "a small bomb" exploded near a UN peacekeeping force observation post in Qassimiyeh, causing damage but no casualties. It did not give details.
This was the second such attack in less than a month. Six Spanish peacekeepers were killed in the last attack on June 24.