Israel claimed rockets had been launched from Gaza during the early hours of Friday morning.
Israel bombed positions of Al-Quds Brigades, the military wing of the Iranian-backed Palestinian group Islamic Jihad, early on Friday in the cities of Khan Younis and Rafah in southern Gaza.
No casualties have been reported so far.
The Israeli army had claimed that rockets had been launched from Gaza during the early hours of Friday morning.
The situation escalated in Gaza on Tuesday after an Israeli air strike killed Bahaa Abu al-Atta, a senior Islamic Jihad commander, and his wife Asmaa.
Two days of fighting between Israel and the Iranian-backed group left 34 Palestinians dead, including eight children and three women.
More than 111 have been injured, including 46 children and 20 women.
A truce was reached in Gaza that went into effect on Thursday at 330GMT, but a lasting ceasefire appeared tenuous due to differences over terms.