A Hamas rocket killed three Israelis north of the Gaza Strip yesterday, drawing the first blood from Israel as the Palestinian death toll rose to 15 in a military showdown lurching closer to all-out war and an invasion of the enclave.
Meanwhile, Arab nations demanded the UN Security Council condemn Israel's deadly attacks on Gaza at an emergency meeting late Wednesday, but the United States strongly defended Israel's military strikes.
The meet called for a halt to the violence, but took no action.
On the second day of an assault Israel said might last many days and culminate in a ground attack, its warplanes bombed targets in and around Gaza city, where tall buildings trembled.
Plumes of smoke and dust furled into a sky laced with the vapour trails of outgoing rockets.
Israel has attacked more than 200 targets in the Gaza since Wednesday night while Hamas militants fired 250 rockets over the border, officials said.
Aside from the deaths, around 150 Gazans have been injured in 22 hours of Israeli air strikes, medics said.
The sudden conflict, launched by Israel with the killing of Hamas's military chief, pours oil on the fire of a Middle East already ablaze with two years of revolution and an out-of-control civil war in Syria. Palestinian allies, led by Egyptian President Mohamed Morsi, denounced the Israeli offensive.
Cairo recalled its ambassador from Israel on Wednesday and asked US to take measures to stop Israeli attacks on Gazans.
The offensive began on Wednesday when a precision Israeli airstrike assassinated Hamas military mastermind Ahmed Al-Jaabari, and Israel shelled the enclave from land, air and sea.
The 15 killed in Gaza included Jaabari and six Hamas fighters plus eight civilians, among them a pregnant woman with twins, an 11-month old boy and three infants, according to the enclave's health ministry. Medics reported at least 130 wounded.
Israel's sworn enemy Iran, which supports and arms Hamas, condemned the Israeli offensive as "organised terrorism".
A second Gaza war has loomed on the horizon for months as waves of Palestinian rocket attacks and Israeli strikes grew increasingly intense and frequent.
Israel Prime Minister Benjamin Netanyahu yesterday said his country will take "whatever action is necessary" to defend its citizens from Palestinian rocket attacks.
His cabinet has granted authorisation for the mobilisation of military reserves if required.
Hamas has said the killing of its top commander In a precision, death-from-above airstrike, would "open the gates of hell" for Israel.