Israeli tanks hit a Hamas post in Gaza after a rocket launched from the Palestinian enclave hit a nearby Israeli city, with no casualties reported on either side.
The rocket fired from the Gaza Strip landed in a street in the southern town of Sderot, the Israeli military has said.
No one was wounded in Wednesday's attack but it marked a rare incident of rocket fire penetrating Israeli's aerial defense system.
Only a handful of projectiles have struck the previously battered town since the conclusion of a 50-day war between Israel and Gaza militants in the summer of 2014.
Sirens warning Sderot residents of the incoming rocket, which landed near a school.
Israel's military typically responds to any rocket fire with air raids in Gaza.
It holds the besieged territory's Hamas rulers responsible for all attacks emanating from the territory.
Since the 2014 war, a ceasefire has largely held, but militants in Gaza occasionally launch rockets toward Israel.