It said on Tuesday that an Iron Dome battery was deployed, without elaborating. The system defends against short-range rockets, and intercepted hundreds of projectiles fired by Palestinian militants during the 2014 Gaza war.
The move follows a warning by Israel’s prime minister and military to Gaza militants against attacks.
Islamic Jihad, an Iran-backed militant group in Gaza, has vowed revenge for the demolition of one of its attack tunnels last month that crossed into Israel.
It was a rare flare-up along the tense border, which has remained mostly quiet since the 2014 Israel-Hamas war.