Israeli soldiers check artillery shells in an area near the border with Gaza amid airstrikes Photograph:( Agencies )
As the violence intensified, Israel said it was carrying out an attack 'in the Gaza Strip' although it later clarified there were no boots on the ground
Israel bombarded Gaza with artillery and airstrikes on Friday in response to a new barrage of rocket fire from the Hamas-run enclave but stopped short of a ground offensive in the conflict that has now claimed more than 100 Palestinian lives.
As the violence intensified, Israel said it was carrying out an attack "in the Gaza Strip" although it later clarified there were no boots on the ground.
Israeli security forces have also been scrambled to contain deadly riots between Jews and Arabs, and projectiles have been fired on Israel from Lebanon.
The United Nations said the Security Council would meet on Sunday to address the conflict, while the US Secretary of State Antony Blinken said Washington was "deeply concerned about the violence in the streets of Israel".
"We believe that Israelis and Palestinians deserve equal measures of freedom, security, dignity and prosperity," Blinken said.
The Israeli army clarified early Friday that its troops had not entered the Gaza Strip as it had earlier stated, blaming an "internal communication" problem for the confusion.
The sound of artillery fire and explosions echoed across northern and eastern parts of Gaza into early Friday morning. Witnesses said many families living in areas near the border quit their homes, some seeking shelter at United Nations-run schools.
Violence also spread to mixed communities of Jews and Arabs in Israel, a new front in the long conflict. Synagogues were attacked and fighting broke out on the streets of some towns, prompting Israel's president to warn of civil war.
At least 109 people were killed in Gaza, including 29 children, over the previous four days, Palestinian medical officials said. On Thursday alone, 52 Palestinians were killed in the enclave, the highest single-day figure since Monday.
Seven people were killed in Israel: a soldier patrolling the Gaza border, five Israeli civilians, including two children, and an Indian worker, Israeli authorities said.
Israel launched its offensive after Hamas fired rockets at Jerusalem and Tel Aviv in retaliation for Israeli police clashes with Palestinians near al-Aqsa mosque in East Jerusalem during the Muslim fasting month of Ramadan.
Brigadier-General Hidai Zilberman, the Israeli military's chief spokesman, said attacks on militants' rocket production and launching sites were "disrupting Hamas' activities", but still not to the point of stopping the barrages.
He said between 80 and 90 militants had been killed in Israeli attacks.
Zilberman said Israel was "building up forces on the Gaza border", a deployment that raised speculation about a possible ground invasion, a move that would recall similar incursions during Israel-Gaza wars in 2014 and in 2009.
Israeli military affairs correspondents, have said however that a major ground incursion is unlikely, citing high casualties among the risks.
Hamas armed wing spokesman Abu Ubaida responded to the troop buildup with defiance, urging Palestinians to rise up.
"Mass up as you wish, from the sea, land and sky. We have prepared for your kinds of deaths that would make you curse yourselves," he said.
So far some 1,750 rockets have been fired at Israel, of which 300 fell short in the Gaza Strip, the Israeli military said.
The hostilities have fuelled tension between Israeli Jews and the country's 21 per cent Arab minority who live alongside them in some communities. Jewish and Arab groups attacked people and damaged shops, hotels and cars overnight.
Although the unrest in Jerusalem was the trigger for hostilities, Palestinians are frustrated by setbacks to their aspirations for an independent state in recent years, including Washington's recognition of disputed Jerusalem as Israel's capital.
On the Israeli political front, Netanyahu's chances to remain in power after an inconclusive March 23 election appeared to improve significantly after his main rival, centrist Yair Lapid, suffered a major setback in efforts to form a government.
(With inputs from agencies)