Hamas has been trying to restore its military capabilities which were mostly destroyed during Operation Protective Edge in 2014. Despite the destruction of 32 of its tunnels by Israel, they have since been feverishly rebuilding a subterranean warren of tunnels to hide in during Israeli strikes and sneak into Israel to carry out future attacks.
In response, Israel began work in June on a 60-kilometer underground barrier penetrating dozens of meters deep which it says will be completed in a few months.
In a briefing with reporters Sunday, an Israeli official showed video footage of heavy machinery raking the sandy border area, a series of holes drilled deep into the ground, a stretch of land the army has flooded, and some controlled explosions. The army's goal, he said, is to turn the underground battlefield into a “death trap” for Hamas.