An explosion early Sunday in southern Lebanon, close to the Israeli border, caused residents to panic and reportedly prompted the Lebanese Army to fire anti-aircraft guns into the air. It's not immediately clear what caused the blast, although Hezbollah supporters are rushing to accuse Israel. 

A suspected Israeli spying device is seen in the southern village of Houla, near the border with Israel, Lebanon, 18 Oct 2009
The explosion, early Sunday, between the southern Lebanese border towns of Houla and Mais al-Jabal is the latest in a series of unexplained blasts to hit the region, over the past month. United Nations peacekeeping forces (UNIFIL) were quickly sent to the area to investigate.

Lebanon's Future TV, quoting a UNIFIL official, indicated that it was too soon to determine exactly what happened, but that "results of the investigation would be announced, as soon as they are available."

Voix du Liban Radio reported that Lebanese Army troops in the garrison town of Marjayoun fired anti-aircraft guns at Israeli drones, which overflew the area. The radio also claimed that the drones destroyed part of a Hezbollah communications link.

Lebanon's official government news agency also accused Israel of blowing up Hezbollah communications equipment, but it was impossible to verify the claim.

The explosion follows another blast, Monday, in the southern Lebanese town of Teir Felsay, which has a strong Hezbollah presence. Hezbollah denied accusations that a secret weapons depot had exploded.

Israel later showed footage taken by a drone, showing men unloading heavy objects from a large convoy of trucks, insisting that they were rockets. Hezbollah claimed the objects were metal garage doors.

Hilal Khashan, professor of political science at the American University of Beirut, calls the series of recent explosions an "ominous sign," and says they give the world community "the impression that Hezbollah is sabotaging the peace and violating U.N. Resolution 1701."

Khashan says that Hezbollah has been giving a long series of excuses for recent explosions that many find difficult to believe:

"An explosion occurred last week, one last night, and one maybe a month ago," said Khashan. "The first two explosions, Hezbollah gave excuses and attributed them to meddling with Israeli leftovers from the 2006 war. Now, it would be extremely difficult for Hezbollah to keep giving us excuses about bombs from the 2006 summer war. So, the pressure will mount on Hezbollah to explain its position. My fear is that these spates of explosions will eventually put the country on another round of war with Israel."

Khashan believes any number of militant groups "could be interested in provoking a conflict with Israel," and might try to set off explosions in Hezbollah weapons depots.