Sirens are being heard as far north as Tel Aviv after a day of sustained rocket fire sent by terrorists operating inside the Gaza Strip.

As the second day of Operation Pillar of Defence came to a close, there was no let-up in southern Israel and civilians in towns near the border were preparing to spend the night in bomb shelters. At least 200 rockets have been fired at Israel in the past day.

Israeli raids on Gaza have also continued, following a strike on senior Hamas military commander Ahmad Jabari on Wednesday afternoon.

Three Israelis have been killed, including 25-year-old Mira Sharf, who was pregnant. More than 100 Israelis have been reported as injured, with two infants wounded after shrapnel went through the room of an apartment building hit by a missile in Kiryat Malachi. In Gaza up to 15 people have been killed, with two children reportedly among them.

A missile fell in an open area of Rishon L'Zion and further north, another is believed - although this has not yet been confirmed by the IDF - to have landed in the water by Jaffa, the Israel-Arab town just south of Tel Aviv. According to reports, Islamic Jihad has taken responsibility for sending it.

"A few minutes ago, sirens in Tel Aviv sent residents running for shelter," the IDF spokesperson said on Twitter. "We can confirm that no rockets struck in the area."

Speaking today, Prime Minister Benjamin Netanyahu pointed out that seven years ago Israel withdrew from Gaza.

"Rather than build a better future for the residents of Gaza, the Hamas leadership, backed by Iran, turned Gaza into a terrorist stronghold.

"They fired thousand of rockets at our cities, at our towns, at our civilians, at our children. They've smuggled thousands of rockets and missiles into Gaza, and they deliberately place these rockets and missiles in civilian areas: in homes, in schools, near hospitals. This year alone, they fired over one thousand rockets and missiles at Israel, including close to 200 rockets in the last 24 hours.

"I'm stressing this because it's important to understand one simple point," he added. "There is no moral symmetry; there is no moral equivalence, between Israel and the terrorist organizations in Gaza. The terrorists are committing a double war crime.

"They fire at Israeli civilians, and they hide behind Palestinian civilians."

White House spokesman Jay Carney stated that the Obama administration strongly condemned the rocket attacks ob civilians. He said there was "no justification" for the "cowardly" violence perpetrated by the terrorist organisations.