The Israel Defence Forces says air and ground troops are “currently attacking” the Gaza Strip .
The latest development comes after Palestinian militants fired more rockets into Israel’s commercial heartland as Israel kept up a punishing bombing campaign in the Gaza Strip and massed tanks and troops on the enclave’s border.
Israeli media are reporting that residents within four kilometres of the border have been ordered into bomb shelters.
Armed forces said it was not a ground invasion, and that troops were firing artillery from Israel’s side of the border.
“I said we would extract a very heavy price from Hamas,” Israeli Prime Minister Benjamin Netanyahu said in a videotaped statement earlier today.
Four days of cross-border fighting show no sign of abating, and Mr Netanyahu said the campaign “will take more time”. Israeli officials said Gaza’s ruling Hamas group must be dealt a strong deterring blow before any ceasefire.
Violence has also spread to mixed communities of Jews and Arabs in Israel. Synagogues were attacked and fighting broke out on the streets of some towns, prompting Israeli President Reuven Rivlin to warn of civil war.
At least 103 people have been killed in Gaza, including 27 children, Palestinian medical officials said. On Thursday alone, 49 Palestinians were killed in the enclave, the highest single-day figure since Monday.
Seven people have been killed in Israel: a soldier patrolling the Gaza border, five Israeli civilians, including two children, and an Indian worker, Israeli authorities said.
Worried about the region’s worst hostilities in years, the United States was sending in an envoy, Hady Amr. Truce efforts by Egypt, Qatar and the United Nations have yet to deliver a sign of progress.
US President Joe Biden called on Thursday for a de-escalation, saying he wanted to see a significant reduction in rocket attacks.
Militants fired rockets at Tel Aviv and surrounding towns, with the Iron Dome anti-missile system intercepting many of them. Communities near the Gaza border and the southern city of Beersheba were also targeted.
Five Israelis were wounded by a rocket that hit a building near Tel Aviv on Thursday.
In Gaza, Israeli warplanes struck a six-storey residential building that it said belonged to Hamas. Netanyahu said Israel had struck a total of close to 1000 militant targets in the territory.
Israeli aircraft also attacked a Hamas intelligence headquarters and four apartments belonging to senior commanders from the group, the military said.
Diplomats said the United States, a close ally of Israel, objected to a request by China, Norway and Tunisia for a public, virtual meeting of the UN Security Council on Friday to discuss the violence.
US Secretary of State Antony Blinken told reporters such a meeting would be better next week to allow time for diplomacy.
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.
A number of foreign airlines have cancelled flights to Israel because of the unrest.
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.
Mr Zilberman said Israel was “building up forces on the Gaza border”, a deployment that has 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 say, however, a major ground operation is unlikely, citing high casualties among the risks.
Hamas armed wing spokesman Abu Ubaida responded with defiance: “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.”
About 1750 rockets had been fired at Israel, of which 300 fell short in the Gaza Strip, the Israeli military said.
British Prime Minister Boris Johnson called for an “urgent de-escalation” and French President Emmanuel Macron urged a “definite reset” of Israeli-Palestinian negotiations.
Russian President Vladimir Putin and United Nations Secretary-General Antonio Guterres also appealed for an end to the fighting.
Although the unrest in Jerusalem was the trigger for hostilities, Palestinians are frustrated by setbacks to their aspirations for an independent state.
In Israeli, Mr Netanyahu’s chances to remain in power after an inconclusive March election appeared to improve significantly after his main rival, centrist Yair Lapid, suffered a major setback in efforts to form a government.