Israel's military has begun an operation to expose and destroy cross border attack tunnels from Lebanon.
They say they've detected tunnels dug by the Iran-backed Lebanese group Hezbollah.
The danger of tunnels was laid bare in 2014.
Israel unearthed cross border tunnels like these going from Gaza to Israel dug by Palestinian militants.
The military saying the current operation would be inside Israel, and not cross in to Lebanon.
Peacekeepers and Lebanese troops were deployed as usual near the border with Israel.
There's been no immediate comment from Hezbollah.
Israel and Hezbollah have avoided any major conflict across the Lebanese-Israeli border since their last war in 2006.
An Israeli military source says this operation might take weeks.