If confirmed, it would mark a violation of a U.N.-brokered cease-fire by Hezbollah and indicate a failure by international peacekeepers to prevent new attacks on Israel. Both Hezbollah and U.N. officials said they were looking into the report.
Lt. Col. Guy Hazoot, the operations officer of Israel's northern division, said an Israeli patrol on Monday discovered and detonated the explosives, which were hidden in containers that looked like boulders. He said the bombs were designed to target Israeli military patrols on the border and were planted as recently as Sunday night, under the cover of the stormy weather.
Israel and Hezbollah fought a 34-day war last summer. The border area has largely remained quiet since the Aug. 14 cease-fire took hold.
Under the cease-fire, thousands of international peacekeepers, along with Lebanese government troops, police the border to ensure quiet. The deal bars Hezbollah guerrillas from carrying arms in the border area.
Hazoot said UNIFIL peacekeepers have thwarted similar Hezbollah attempts to lay roadside bombs in the past, but had failed to do so this time.
"We view the Lebanese army as responsible for this event," he said, and warned. "We will take all the necessary steps to make sure that these such events do not recur."
A Hezbollah official in Beirut said the group was checking the Israeli report.
Liam McDowall, a UNIFIL spokesman in Lebanon, said Israel had notified the peacekeeping force about the explosives. "We have sent a team to look into the matter and see what was detonated," he said.