JERUSALEM — The combat engineer captain pulled up photos on his phone. Tunnel after tunnel. Underground weapons cache after weapons cache. All blown to pieces.

"We found over 1,000 terror sites in five weeks," Lt. Col. "R" told The Jerusalem Post from his base north of Eilat. His 603rd Combat Engineering Battalion has been systematically dismantling Hezbollah's southern Lebanon infrastructure since March 10. The scale surprised even veteran engineers.

This is different from Gaza. Completely different.

What the engineers found in Lebanon

Battalion 603 operates as part of Division 36, which pushed deeper into Lebanese territory than most of the other five IDF divisions now fighting there. The terrain changed everything about how they work.

"We were experts in Gaza topography," R said. "We knew the land, and the land is a key piece of combat engineering. We knew how to achieve great results, destroying tunnels, and cornering or killing Hamas terrorists."

Lebanon forced them to relearn their trade. Different soil composition. Different construction methods. Different hiding spots.

The 37-year-old Ramat Gan native has commanded Battalion 603 for 10 months, following stints as combat engineering officer for Division 162 and the elite Yahalom unit. His fighters finished three months in Rafah six weeks ago, where they killed 24 Hamas operatives in close-quarters fighting and tank assaults.

They expected rest. They got one week of training before Lebanon called.

The infrastructure that keeps growing

Hezbollah built differently than Hamas. More sophisticated. More redundant. The engineers keep finding new sites.

"Endless amounts" of terror infrastructure, R called it. Not just tunnels — weapons storage, command bunkers, rocket launching positions built into civilian areas. Each site requires different demolition techniques.

The battalion uses drones and robots to map underground networks before sending in human teams. Standard practice now across all five divisions operating in Lebanon. But the volume of targets keeps growing.

Battalion 603 operates heavy engineering vehicles alongside infantry and armor units. They clear paths, demolish fortifications, and eliminate underground threats that could ambush advancing forces.

R's unit spent their first week in Lebanon developing new tactical plans. The topography demanded it. Hills instead of urban density. Stone instead of concrete. Ancient construction mixed with modern military engineering.

Different war, same enemy

The transition from Gaza to Lebanon took more than geographic adjustment. Hamas builds tunnels for smuggling and surprise attacks. Hezbollah builds entire underground cities designed to survive sustained bombardment.

"The massive changes in topography after having spent over a year serving in Gaza were significant," R explained. His engineers had to learn new demolition techniques for different geological conditions.

Battalion 603 finished their Gaza deployment around six weeks ago after months of operations near the Yellow Line in Rafah. They killed two dozen Hamas fighters and destroyed multiple tunnel networks. Then came the call north.

The 603rd belongs to the 7th Brigade, which has been rotating between Gaza and Lebanon as the war expanded. Combat engineers prove essential in both theaters — different techniques, same mission.

What Division 36 sees

Division 36 penetrated deeper into Lebanese territory than most other IDF divisions. That puts Battalion 603 in areas where Hezbollah had years to prepare defensive positions.

The infrastructure reflects long-term planning. Not hasty wartime construction but permanent installations designed to support extended operations against Israel. Some sites took days to fully clear and demolish.

R expects to continue commanding Battalion 603 for another one to two years. His 19-year IDF career includes combat engineering roles across multiple units. The Lebanon deployment represents his most complex engineering challenge yet.

His fighters adapted quickly. The same skills that worked in Gaza — drone reconnaissance, robotic mapping, precision demolition — apply in Lebanon with tactical modifications.

But the scale keeps expanding. Every cleared village reveals new underground networks. Every demolished position leads to three more discoveries.

The numbers that matter

Over 1,000 terror infrastructure sites destroyed in five weeks. That averages nearly 30 sites per day across the battalion's area of operations. Each site requires engineering assessment, tactical planning, and controlled demolition.

The pace reflects both Hezbollah's extensive preparations and the IDF's systematic approach to clearing southern Lebanon. Division 36 operates in coordination with five other divisions, each targeting different sectors of Hezbollah's defensive network.

R's battalion collected all necessary equipment and serviced their heavy vehicles during one week of preparation before entering Lebanon. Combat engineering requires specialized tools and extensive logistical support.

The operation continues. More sites discovered daily. More demolitions planned. The underground war that Hezbollah spent decades preparing now faces systematic destruction by engineers who learned their trade in Gaza's tunnels.

Battalion 603 returns to base north of Eilat between rotations. Brief rest, equipment maintenance, tactical updates. Then back to Lebanon's hills and Hezbollah's endless infrastructure.

The next rotation begins in two weeks. More tunnels await demolition.