Israel's military said on Tuesday it had begun an operation to "expose and thwart" cross-border attack tunnels from Lebanon dug by the Lebanese militia Hezbollah.
Israeli military spokesman Lt. Col. Jonathan Conricus said the military had detected tunnels crossing from Lebanon into northern Israel.
He said the Israeli operation to counter the tunnels would be inside Israel, and would not cross the border.
Israel released video footage of digging and pile-driving equipment at work in unidentified locations with trees and bushes in the background, carrying out what it said were "tactical preparations to expose Hezbollah's offensive cross-border tunnel project."
Reuters could not immediately verify the footage.
On Monday, Netanyahu met with U.S. Secretary of State Mike Pompeo in Brussels. An Israeli government source said the purpose of the meeting was to update Pompeo of the upcoming tunnel operation.
The current focus of operations was near the Israeli border town Metulla, Conricus said, adding that some areas near the border fence had been closed off.
An Israeli military source said the operation might take weeks to complete.
Hezbollah, founded in 1982 by Iran's Revolutionary Guards, has grown stronger since the 2006 war with Israel, notably through its role in the Syrian war fighting in support of President Bashar al-Assad.
Over the past decade, Israel and Hezbollah have largely maintained a stand-off - the group has rarely launched attacks into Israel from Lebanon and Israel has rarely struck against the group on Lebanese soil.
But in the past few years Israel has struck dozens of times inside Syria at what it said were advanced weapon deliveries to Hezbollah.
*This story was edited by Ahram Online