Hezbollah operatives have been scrambling in the last few days to seal off tunnels they dug into Israeli territory, according to Israeli army sources on Tuesday, although no explanation was given as to why the activity has not triggered explosives that the Israel Defense Forces rigged at the sites.

Four massive terror tunnels have been exposed so far, as the IDF engages in “Operation Northern Shield,” a mission to thwart attacks on Israel from the country’s northern enemy, Hezbollah.

According to the IDF, one of the tunnels was already partially sealed by the Hezbollah, despite the fact that the army had affixed a booby trap to prevent terrorists from entering it.

Officials did not say which tunnel was sealed or why, or how the entrance of the terrorists failed to set off the explosives.

The army said the tunnels are under constant surveillance as they are being prepared for demolition, and that they do not present an immediate threat of danger to nearby Israeli communities.

The U.N. Interim Force in Lebanon’s (UNIFIL) border patrol force said the tunnels “constitute violations of U.N. Security Council Resolution 1701,” which call for all military groups in Lebanon to remain north of the Litani River.

The international body did not say how illegally positioned terrorists managed to construct the large and illegal tunnels into Israel, despite their supervision of the area.

Lebanese Prime Minister Saad Hariri met with UNIFIL commander Maj. Gen. Stefano Del Col on Monday, telling him his country intended to “conduct patrols to deal with any flaw in the implementation of Resolution 1701 from the Lebanese side,” according to official Lebanese state media outlet National News Agency.

Hariri also accused Israel of conducting “daily violations … of Lebanese airspace and territorial waters.

According to NNA, Hariri also called on the United Nations to “shoulder its responsibilities in facing the daily violations by Israel of Lebanese airspace and territorial waters.”

On Monday, Israeli and Lebanese troops came face to face along the border, and began engaging in a war of words with guns drawn. The alleged source of the argument was the placement by Israel of a concertina wire along the Blue Line as part of efforts to dismantle the tunnels.

UNIFIL workers were on the scene.