JERUSALEM, Dec. 6 (Xinhua) -- Israeli Prime Minister Benjamin Netanyahu on Thursday visited the border with Lebanon, saying that Israel will do "whatever is necessary" to prevent the Hezbollah building cross-border tunnels.

His remark was made two days after Israel's army launched the "Northern Shield" operation to "locate and thwart" tunnels dug by the Lebanese Shiite military of Hezbollah.

He spoke during an official tour for foreign ambassadors in northern Israel near where the army units are acting to locate the tunnels.

Led by the Commander of the Northern Command, Yoav Strick, and Head of the Planning Ground Arm Command, Amir Abulafia, the ambassadors toured the area of a tunnel that the Israeli army uncovered on Tuesday.

"We are systematically and decisively denying the tunnels weapon," Netanyahu said during the tour, adding that "whoever attacks us is taking his life into his hands."

"Israel expects an unequivocal condemnation of Hezbollah, the imposition of additional sanctions on Iran, a condemnation from the Lebanese government and a demand that it stops giving approval for the use of its territory for these attacks against Israel," Netanyahu told the ambassadors.

Also on Thursday, a senior Israeli official on condition of anonymity told local media that the Israeli army might extend the operation and take actions inside Lebanon.

The tunnels "are wider and larger, and their goal is to transfer entire battalions and large forces into Israeli territory, kidnapping and capturing Israeli towns and villages," said the official.

On Wednesday, Lebanon's Parliament Speaker, Nabih Berri, said during a meeting with the United Nations Interim Forces in Lebanon (UNIFIL), the UN peacekeeping force, that Israel provided no evidence for cross-border tunnels.