Gaza militants fired rockets and mortars into Israel Wednesday, prompting retaliatory airstrikes by Israel following a surge of cross-border attacks on Tuesday.
News reports say at least one rocket hit the southern city of Beersheba Wednesday, while a rocket fired overnight landed near the port city of Ashdod.
The Islamic Jihad militant group claimed responsibility for the rocket attacks. The group said it fired the rockets in response to Israel's deadly raids Tuesday in the Gaza Strip.
Palestinian officials say the Israeli military strikes killed eight people, including four civilians.
Medical sources said Israeli shelling Tuesday on a house in Gaza City killed three children and an adult. The Israeli military said the strike was aimed at Palestinian militants who fired mortar rounds into Israel.
Israeli Prime Minister Benjamin Netanyahu voiced regret about the loss of innocent life. But he said it is unfortunate that Hamas continues to fire rockets at Israeli civilians.
United Nations Secretary-General Ban Ki-moon condemned the killing of the four Palestinian civilians, and reiterated his condemnation of rocket fire by Gaza-based militants. Ban said he is very concerned about the rising violence in Gaza and southern Israel.
Israel has increased its strikes against Gaza militants in response to a barrage of mortar attacks from the Palestinian territory in recent days.
Hamas officials have threatened to retaliate for the deaths of the Gazans.
Some information for this report was provided by AP, AFP and Reuters.