Israel's Iron Dome defense system went into action on Sunday to intercept Palestinian machine-gun fire from the Gaza Strip, not against incoming rocket fire, the military said.
Flaming streams from about 10 Iron Dome interceptors could be seen rising into the night sky in a spectacular light show.
But there was no indication that Gaza-based terrorists had fired rockets at Israel, an IDF spokeswoman said.
"Following reports of [warning] sirens sounding in southern Israel, unusual machine-gun fire toward Israel was identified. No rocket fire was identified. The IDF is looking into the circumstances that led to the Iron Dome system engaging."
The IDF said it continues to hold Hamas responsible "for any terrorist activity emanating from the Gaza Strip" and that, in response to the machine-gun fire into Israel, an Israeli tank targeted two observation posts in the northern Gaza Strip.
Hamas military wing spokesman Abu Obaida said no rockets were fired at Israel.
The fire was apparently part of a large military exercise Hamas held on Sunday, against the backdrop of heightened tensions with Israel.
During the drill, Hamas operatives set off explosions and test-fired rockets into the sea off the Gaza coast. Gunfire echoed across the coastal enclave as hundreds of operatives deployed for the exercise, which was due to continue on Monday.
"The enemy [Israel] bears responsibility for any escalation and we will not stand handcuffed against any aggression," Abu Obaida said.
Hamas is planning a mass protest near the border on Friday. The terrorist group has urged Gaza residents to gather near the fence and march toward Israeli positions with the intention of crossing into the Jewish state.
Bracing for potential violence, the IDF Southern Command began bolstering deployment along the border on Friday, adding clusters of coiled barbed wire at sites where military bulldozers are working on the IDF's underground tunnel barrier, to prevent protests from reaching the area and potentially sabotaging the project.
The IDF also plans to deploy additional machinery along the border and have snipers at the ready.
The troops have been instructed to exercise maximum restraint so as to minimize the number of Palestinian casualties.
