Apparently, the heavy rains from last week collapsed the tunnel.
The IDF spokesperson stated that "This attempt to carry out terrorist attacks against citizens and security forces in Israeli territory is viewed in very serious terms by the army."
Large army forces were rushed Monday to an open terrain to investigate a ground collapse close to the Nir Oz community, located not far from the border fence.
Apparently the collapse wasn't due to an explosion, and bomb experts and Engineering Corps soldiers examined the terrain and discovered the tunnel entrance. An investigation into the tunnel's origin and construction date in ongoing.
the likely purpose of this tunnel was to kidnap Israelis or to perform a major terror attack within Israel.
Which brings up the question of how many other such tunnels there are under the Gaza border towards Israel, today?