Three Israelis have been killed after a rocket fired from Gaza hit the town of Kiryat Malachi.
The two women and a man, all aged in their 30s, were in a four-storey building which suffered a direct hit.
The trio were later named as Aharon Smadga, 49, Itzik Amsalem, 24, and Mirah Sharf, 26. Israeli media reports claimed Ms Sharf was pregnant and had been visiting Israel on a trip from India to attend a memorial service for those killed in the 2008 terrorist attacks on Mumbai.
An eight-month-old baby was critically injured in the attack on Thursday morning.
They were the first Israeli deaths following the IDF strike which killed Hamas military leader Ahmed Jabari on Wednesday in the first steps of Operation Pillar of Defense.
Israel’s Iron Dome missile defence system intercepted dozens of Palestinian rockets fired overnight, but a number of rockets landed near Be’er Sheva, Ashkelon and other southern Israeli towns and cities.
More than 100 terrorist targets in Gaza have been targeted by Israel since the Jabari strike, with five Palestinian rocket-launching squads thought to have been eliminated.
It is thought around 11 Palestinians, including terrorists and civilians, have been killed in the Israeli operation.
Hamas claims it has fired rockets at Tel Aviv, but the IDF has yet to confirm whether such strikes took place.
The Zaka emergency response group confirmed it had held an emergency meeting and was equipping members across Israel with bullet-proof vests and helmets.
"I live in the adjacent street to the building which received a direct hit," said Yedidah Halevy, Zaka volunteer in Kiryat Malachi.
"I heard the explosion and ran in the direction of the smoke. Other Zaka and MDA volunteers arrived with me at the scene. We began to treat the injured. To my sorrow, two men and a woman were killed on the top floor of the building.
"The apartment suffered a direct hit, with shrapnel throughout the rooms."
