SIDDIQIN, Lebanon: An explosion shook a Hezbollah stronghold near Siddiqin in the Tyre region of south Lebanon overnight, a security source told The Daily Star Wednesday.

The Lebanese Army released a statement Wednesday afternoon saying that the explosion was likely the result of a landmine or a cluster bomb left over from the July-August war between Lebanon and Israel in 2006.

Earlier Wednesday, the security source, who spoke on condition of anonymity, said the cause of the blast, which was heard shortly before midnight, could not be determined due to a heavy security blanket by Hezbollah that followed the explosion.

In its statement Wednesday, the army said it had searched the area but found no trace of the explosion as it “left no visible effects.”

Early in the day, local media said the explosion likely took place at a Hezbollah arms cache.

In a statement later in the day, Hezbollah denied that the explosion in south Lebanon was a result of an explosion at an arms depot.

"What has been circulating in the media regarding the explosion in Sidiqqin and that it is related to storage center for Hezbollah is utterly false,” the party said in the statement.

Four Israeli warplanes were spotted flying over Siddiqin at around 10.00 a.m. and patrols by the United Nations Interim Force in Lebanon were active in the area. A UNIFIL helicopter could also be seen flying over the village.

A spokesman for the U.N. peacekeeping force said UNIFIL had heard about the explosion on the news.

"We have no information at the moment. We are checking this report," Andrea Tenenti told The Daily Star by telephone.