Palestinian militants fired a rocket into Israel on Saturday (November 21) night, prompting Israeli air strikes in the Gaza Strip, Israel's military said on Sunday (November 22).
There were no casualties reported on either side of the border.
Israeli police said the Gaza rocket damaged a factory in the southern city of Ashkelon.
The Israeli military said its aircraft struck in response against several military sites belonging to Hamas, the armed Islamist group that controls Gaza.
Reuters witnesses said the pre-dawn strikes hit targets in Gaza City and the southern Gaza cities of Rafah and Khan Younis.
There was no immediate claim of responsibility from any of Gaza's military groups for firing the rocket.
Israel and Hamas last fought a war in 2014 and have exchanged fire several times since.
But the border has been largely quiet in recent months.
In Gaza, a Hamas spokesman blamed the new escalation on Israel.