Israeli air strikes hit Gaza towns on Sunday morning, targeting fighters from Palestinian group Islamic Jihad, the military said.
Two airstrikes hit the southern town of Khan Younis, targeting positions of the Al-Quds Brigade, the armed wing of Islamic Jihad. The third was near the southern town of Rafah, near the Egyptian border, Palestinian witnesses told AFP news agency.
The Israeli military said the attack was in response to a rocket that Palestinian fighters fired from the territory into southern Israel.
The Democratic Front for the Liberation of Palestine told Reuters the air strike hit a training base belonging to the group in Rafah in the southern Gaza Strip but nobody was hurt.
Israel had not carried out Gaza airstrikes since early April, when it launched the first strikes since an Egyptian-brokered truce in November ended a deadly eight-day conflict between the Jewish state and militants of Islamist movement Hamas, which rules the territory.
On April 19, two rockets fired from the Gaza Strip hit southern Israel without causing any casualties or damage.