Sderot: The boom of mortar fire and air strikes rocked both sides of the Israel-Gaza border well into the night, as air raid sirens sounded in Israel's largest city, Tel Aviv, for the first time in 20 years.
Israel has made it clear that it will not tolerate rocket and missile attacks on its civilians.
Attempts by Egypt to broker a ceasefire in Cairo have reportedly led nowhere, leaving many in Gaza and southern Israel fearing the worst may be yet to come.
Tension ... protesters wave Palestinian flags in front of Israeli soldiers during a protest against Israel's military operation in Gaza. Photo: Reuters
Both the Israeli Prime Minister, Benjamin Netanyahu, and the Hamas Prime Minister, Ismail Haniyeh, gave defiant speeches, each vowing to defend their people and hit back against the escalating violence.
Israel said 274 missiles had been fired from the Gaza Strip into Israel since Wednesday afternoon, when an Israeli air strike killed the military leader of Hamas, Ahmed al-Jabari.
The rocket fired at Tel Aviv – believed to be an Iranian made and supplied Fajr-5 with a range of about 60 kilometres – fell into the sea just near the port of Jaffa to the south of the city, an Israeli security source said.
Defiant ... Israel's Prime Minister Benjamin Netanyahu. Photo: Reuters
A second rocket landed in an open area near the neighbouring city of Rishon Le'Tzion, officials said, indicating a serious shift in Hamas tactics by aiming their attacks towards central Israel.
In response Israel reportedly launched a ferocious air and sea assault on Gaza, hitting as many as 80 targets in just 30 minutes, with the home of an al-Aqsa Brigade commander among those hit. There was no confirmation of casualties from this attack, although reports indicate at least 115 people have been injured since Wednesday, among them 25 women and 26 children, the Palestinian Centre for Human Rights reported.
Israel was keeping all options open, including a possible ground assault, said the spokesman for Mr Netanyahu, Mark Regev.
The funeral for Aharon Smaja, 49, one of the three people who died in a rocket attack. Photo: Getty Images
"What we saw today with the alert in Tel Aviv shows we are dealing with a formidable terrorist regime," he told the BBC. "We have to deal with this threat to protect our people." He declined to confirm reports that Israeli troops were massing on the Gaza border.
So far 18 people have been killed, including at least three Israeli civilians who died as they tried to flee to a fortified stairwell in their four-storey building in Kiryat Malachi. In Gaza, 15 Palestinians died, including a number of militants, as well as four Palestinian children and a woman pregnant with twins.
Israel has continued to leave the threat of a ground offensive in Gaza on the table, with the Defence Minister, Ehud Barak, reportedly approving calling up more than 30,000 reservists.
Grief ... the BBC journalist Jihad Misharawi weeps while he holds the body of his 11-month old son Ahmad. Photo: AP
Associated Press has reported Israeli forces were moving toward the Gaza border, while the sight of at least two large Israeli tanks being transported on the back of trucks travelling south towards Gaza last night may provide further indication of Israel's preparation for a land assault.
After the deaths of Israelis Aharon Smajda, 49, Itzik Amsalem, 24, and Mirah Sharf, 27 - who was reportedly pregnant – Mr Netanyahu accused Hamas of committing war crimes. “No government would tolerate a situation where nearly a fifth of its people live under a constant barrage of rockets and missile fire, and Israel will not tolerate this situation," he said.
“This is why my government has instructed the Israeli Defence Forces to conduct surgical strikes against the terrorist infrastructure in Gaza … to take whatever action is necessary to defend our people.”
Attacks escalate on the Israel-Gaza border
Tension rises in the Middle East as mortar fire and air strikes rock both sides of the Israel-Gaza border. Photo: AFP
Speaking in Gaza overnight, Mr Haniyeh accused Israel of “cowardly and shameless aggression that is used to kill innocent people, children, women and men”.
“It is the [Israeli] occupation that is fully responsible for the state of war,” Mr Haneiyah said.
Hamas, an Islamist movement considered a terrorist group by Israel, the US and the European Union, appealed to Egypt's Muslim Brotherhood leaders for help, and on Friday that help is expected to arrive with a visit from Egyptian Prime Minister Hesham Kandil to the tiny coastal enclave.
Israel's leaders say the assassination of Ahmed al-Jabari was necessary to defend its civilians against a relentless barrage of rockets fired into southern Israel. But Hamas says Israel initiated the recent outbreak of hostilities when its soldiers killed a 13-year-old Palestinian boy, Ahmed Younis Khader Abu Daqqa, who was shot while playing football with friends in front of his house in the ‘Abassan village, near the southern Gaza town of Khan Yunis.
Hospitals in Gaza were struggling to cope with casualties and running dangerously low on basic supplies, the human rights group Medical Aid for Palestinians said. And in further reports of civilian casualties, an Arabic teacher at a UN school was killed and his brother severely injured in an Israeli airstrike, said Christopher Gunness, a spokesman for the United Nations refugee agency UNRWA.
Thousands lined the streets of Gaza on Thursday for the funeral of Mr Jabari, who was killed in an Israeli air strike as he drove through a heavily populated area in Gaza City.
The devastated family of the BBC journalist Jihad Misharawi mourned the death of his 11-month-old son Omar, killed along with his sister-in-law when an Israeli mortar shell crashed through their house as the attacks escalated on Thursday.