Israeli planes struck at Palestinian Islamic Jihad sites in the Gaza Strip in answer to more than 20 rockets launched into southern Israel on Sunday evening.
Shortly after the IAF counterattack began, sirens again wailed in Sderot and surrounding communities, sending thousands of residents rushing for cover.
There were no immediate reports of injuries on either side.
The IDF said one of its aircraft targeted a Palestinian Islamic Jihad squad preparing to launch rockets from northern Gaza.
“A hit was confirmed,” the IDF said.
The terror group had taken responsibility for the rockets launched against Israel earlier in the evening.
Meanwhile, more trouble was anticipated through Monday. The Homefront Command issued guidelines, in effect until Monday evening, prohibiting outdoor activities in the Ashkelon, Eshkol, Hof Ashkelon, Netivot, Sderot, Sdot Negev and Shaar Hanegev areas.
Indoor gatherings in those areas will be limited to 300 people.
Schools will be closed in Ashkelon, Sderot and Netivot on Monday.