An IDF drill that was digging into a Hamas attack tunnel to destroy it on Thursday night triggered a bomb planted inside, leading to the injury of five soldiers, a senior IDF source said Friday.
Hamas planted the bomb - made up of explosives and diesel fuel - on the Gazan side of the tunnel in early October, a few days after the IDF exposed the 1.7 kilometer-long structure, according to the IDF's assessment.
The explosive was intended to kill, maim, or facilitate the kidnapping of soldiers that Hamas expected the IDF to send into the Gazan side of the tunnel to destroy it, the IDF believes.
Instead, the army chose to destroy the tunnel from overground, sending a task force composed of the Yahalom elite Combat Engineering Corps unit, Golani infantry brigade soldiers, and units from the 401st Armored Brigade over the security fence, a hundred meters into Gaza, to carry out the job.
"The drill set off the bomb, creating shock waves, which injured the soldiers. We would never send our soldiers into the tunnel before mapping it out with dogs and robots first. We didn't reach that stage in the operation," the senior army source said.
"The blast injured six soldiers and commanders; one seriously and the remainder lightly. No one is in a life-threatening condition," he added. One of the wounded was a team commander overseeing demolition work. Five of the soldiers were air lifted to the Soroka Medical Center in Beersheba.
"Despite the injuries, we continued the mission until its completion," the source said. The IDF inserted new commanders to replace the wounded, and oversaw the completion of the drilling operation.
Just after the drill set off Hamas's bomb, the IDF identified a terrorist cell spying on the army's activities from a distance of just over a kilometer away, in Gaza's Khan Younis district.
The cell included one man armed with an anti-tank missile launcher and a second who acted as a lookout. An Israeli tank fired a shell in their direction, killing one terrorist and seriously injuring a second.
The IDF then lowered an enormous 2,800 kilogram bomb into the drilling site, 90 meters inside Gaza, and detonated it, leading to the tunnel's collapse. shortly before 11 p.m. on Thursday night.
Hours later, at approximately 5 a.m. on Friday, an Israel Air Force jet struck the tunnel's shaft in Gaza, which was located 1700 meters from the border, hidden under a Palestinian hothouse.
The missile strike also killed three senior Hamas commanders who were in the vicinity. The commanders were situated underground in a parallel tunnel that was linked to the tunnel hit by the IAF.
The men were high-ranking experts in tunnel warfare from Hamas's Khan Younis Division. One was also a rockets expert.
"Last night, we acted offensively in regards to the terror tunnel we exposed," the source said. "We believe that as soon as Hamas saw that we uncovered its tunnel, it planted the explosive. We prepared for this possibility. We will investigate this incident - I'm sure we will learn from it," he added.
The IDF's aim, he continued, is to turn Hamas's advantage in tunnel warfare into a disadvantage. "Hamas thought its tunnel was a secret. We showed it we have the ability to expose it... and we helped Hamas understand that their tunnels can go from hideouts to graves."
"We're investing a lot into combating tunnels and exposing them, including the introduction of new technologies for this," he added.
The IDF believes that Hamas will not respond to the recent incidents, due to Israeli deterrence, and its growing economic troubles and regional isolation. "I don't see any preparations by Hamas to act," the source said.
He described the successful demolition of the tunnel as an impressive achievement that was completed despite "disruptions to the chain of command."
"Last night, we found that despite the shortage of diesel fuel for Gaza's power plant, Hamas is diverting the fuel to create bombs, just as it used Israeli concrete sent into Gaza for the civilian construction sector to build the terror tunnel," the source said.
The IDF has placed Iron Dome air defense batteries around southern communities in preparations for the possibility of an escalation. But following an evaluation held on Friday morning, it decided to instruct civilians in the south to proceed as normal.