Prime Minister Benjamin Netanyahu said late on Tuesday the tunnels were a grave violation of Israeli sovereignty.
"Only two weeks ago I said that in order to ensure the security of Israel, we need to be patient and stay calm".
Israeli army spokesman Lieutenant Colonel Jonathan Conricus said the "attack tunnels" were not yet operational. Had the tunnels not been detected, Radwan terror cells could have made their way through the tunnels, underneath Israel's extensive border defenses (which include an array of sensors, an above-ground barrier, and artificial cliffs), and entered northern Israel.
Lebanese troops and military intelligence agents, along with United Nations peacekeepers deployed in southern Lebanon, were observing the border Tuesday, a Lebanese military official said, speaking on condition of anonymity in line with regulations. The army declared the town of Metulla, located on the Israeli-Lebanese border not far from the occupied Golan Heights, a closed military zone. "Hezbollah uses the tunnels for strategic operations, and it's a big difference".
Conricus said the timing of Operation Northern Shield was guided by the "maturation of different capabilities that will allow us to feel confident enough to find the tunnels".
Israel's vulnerability to tunnels was laid bare during its war with Palestinian militant group Hamas in Gaza in 2014 when Palestinian militants used dozens of secret passages dug from Gaza into Israel to launch surprise attacks.
No tunnels from Lebanon include exit points within Israel, the army said.
Additionally, the Lebanese army command said that it is watching the situation closely, reiterating its readiness to confront any emergency situation.
The military is destroying the tunnels from Israel's side of the border.
The prime minister, who has since assumed the role of defence minister, said at the time that holding elections would be "irresponsible" due to the undefined security threats.
"He's half the Israeli government, practically", Kiriakou commented on what is considered to be the "one genuine democracy in the Middle East" by outgoing US Ambassador to the UN Nikki Haley.
Prominent regional analyst Abdel Bari Atwan, the editor-in-chief of Rai al-Youm, wrote Tuesday that the Israeli premier is struggling to save his own political life and avoid ending behind bars for graft by announcing such an operation.
Israel views the Iranian-backed Hezbollah and its vast weapons cache as a major threat.
There has been increased attention in Israel in recent days over Israeli officials' concerns regarding Iranian activity in Lebanon.
"Hezbollah is a risky terror organization acting out of Lebanon under the orders of Tehran, and its objective is to inflict damage to Israel and to Israeli citizens".
However, a friendly fire incident in Syria in September that led to the downing of a Russian plane by Syrian air defences during an Israeli strike has complicated Israeli operations there.