Islamic Jihad, a militant group with some links to Hamas, the Islamist movement in charge of Gaza, said it had fired more than 100 rockets on Friday into Israeli cities, including Tel Aviv. Israel's ambulance service said there were no reports of casualties.
Earlier, local health officials in Gaza said at least 10 people, including a five-year-old child, had been killed and 55 wounded in the Israeli airstrikes, which came after days of escalating tensions following the arrest of a Palestinian militant leader during the week.
An Israeli spokesperson said the strikes had killed Islamic Jihad commander Tayseer al-Jaabari and around 15 "terrorists" but said the military did not have a final casualty total.
Israeli Prime Minister Yair Lapid said in a televised statement that Israel would do "whatever it takes" to defend its people.