Prime Minister Benjamin Netanyahu said he regretted the accidental killing of four members of a Palestinian family in their Gaza home by Israeli tank fire.

Netanyahu in a statement Tuesday from the Prime Minister's Office emphasized that the shooting was in response to fire by Hamas at Israeli citizens.

"It is unfortunate that Hamas continues to rain down dozens of rockets on Israeli civilians intentionally using civilians as shields," he said. "Israel has no intention of bringing about a deterioration of the situation, but at the same the IDF will continue to act decisively to protect Israeli citizens."

Later Tuesday evening, three gunmen from the al-Quds Brigades, the armed wing of Islamic Jihad, were killed in an Israeli airstrike, according to the Palestinian Ma'an news agency. The Israel Defense Forces said it struck terrorists on their way to launch rockets at Israel; the IDF identified them as the terrorists who launched a Grad-style rocket on Beersheba last month.

A Kassam rocket fired from Gaza struck Ashkelon shortly after.

Some 13 other Palestinians, including children, also were injured in Tuesday afternoon's strike, which came after four Kassam rockets fired from Gaza hit southern Israel, according to reports. Israeli troops fired in the direction of Palestinians who had launched mortars at them, accidentally hitting the home, reports said.

Also Tuesday, Israeli troops fired on Gaza Palestinians preparing to launch an anti-tank missile at an Israeli force operating in the northern Gaza Strip. The IDF in a statement said its soldiers hit their target.

Israeli combat planes late Monday night pounded the Gaza Strip in retaliation for a weekend mortar attack, the worst barrage of rocket attacks on southern Israel in two years. More than 50 mortar shells struck the area on Saturday morning. On Monday, a long-range Grad-style rocket was fired from Gaza at southern Israel.

The Israelis' attack hit two terror tunnels, two weapons manufacturing and storage facilities and two additional terror activity sites across the Gaza Strip, according to the IDF. Israel Radio said there were reports from Palestinian sources of 17 wounded.

Israel had responded earlier Monday to Saturday's barrage with airstrikes on suspected bomb smuggling tunnels. The latest attack seemed more comprehensive and sustained, according to Israel Radio.

The armed wing of Hamas, Izzadin Kassam Brigades, had claimed responsibility for most of the explosives sent Saturday from Gaza.

Before Israel's attack Monday night, a spokesman for Hamas, the terrorist group that controls Gaza, had indicated that the group was ready to return to a fragile truce.