ISRAELI ground forces are on standby to enter the Gaza Strip after the Israel Defence Forces said they had hit more than 100 ''targets'' in the besieged coastal territory, an offensive that began with the assassination of Hamas commander Ahmed al-Jabari in a missile strike in Gaza City.
In response, Hamas's armed wing warned the assassination ''had opened the gates of hell'' and vowed its militants would ''continue the path of resistance''.
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Gaza missile strike raises war fears
An Israeli missile strike on Gaza, which killed the head of the Islamist organisation's military wing, has increased fears of an escalation of conflict in the region.
The Israeli Prime Minister, Benjamin Netanyahu, warned that the military was ''prepared to expand'' its operation.
The IDF said its actions were part of a wider Israeli operation against militant groups and weapons sites in the Hamas-run Gaza Strip, and were prompted by a wave of rocket attacks against Israel.
Gaza's Health Ministry said 10 civilians have been killed, including two young children - an 11-month-old and a six-year-old - while at least 45 people had been wounded; 10 of them were in a critical condition.
There were scenes of chaos at Shifa Hospital in Gaza City, as dozens of seriously injured patients were stretchered in, while ambulances sped off to collect more casualties.
In southern Israel, residents have been ordered to stay in bomb shelters in preparation for an expected surge in rocket attacks from Gaza. Schools in a 40-kilometre radius of the border have closed.
Hamas, an Islamist movement considered a terrorist group by Israel, the US and the European Union, has appealed for help from the new Muslim Brotherhood leaders of Egypt.
The Egyptian President, Mohammed Mursi, recalled the country's ambassador to Israel and called for an urgent meeting of the Arab League.
The Egyptian Foreign Minister, Mohamed Kamel Amr, called on Israel to stop the strikes immediately, warning an escalation from Israel ''could have negative repercussions on the security and stability of the region''.
Fighting words in the Middle East
Israeli Prime Minister Benjamin Netanyahu says Gaza militants are committing multiple war crimes, as Hamas promises the violence will escalate.
The United States threw its weight behind Israel.
''We support Israel's right to defend itself, and we encourage Israel to continue to take every effort to avoid civilian casualties,'' US State Department spokesman Mark Toner said. ''We strongly condemn the barrage of rocket fire from Gaza into southern Israel, and we regret the death and injury of innocent Israeli and Palestinian civilians caused by the ensuing violence,'' he added.
Thirteen rockets fired from Gaza into southern Israel had been intercepted by the country's missile defence system, the IDF spokesperson said, tweeting with the tag #PillarofDefense. ''We recommend that no Hamas operatives, whether low-level or senior leaders, show their faces above ground in the days ahead,'' the spokesperson said.
Saeb Erekat, a member of the Palestine Liberation Organisation's executive committee and chief Palestinian negotiator, condemned the attacks as an attempt to ''initiate a bloody escalation''.
''We hold the Israeli government fully responsible for the consequences that this new act of aggression would bring to the region.'' Mr Erekat said. ''This exposes that Israel has an agenda for war but not for peace.''
One Gaza resident, a doctor, posted this on her Facebook page: ''Gaza is under extensive Israeli military attack … the hospitals are already lacking essential emergency medications, and citizens were called for blood donation, we do not have power … we expect more escalation.''
The video of Jabari's assassination was posted on YouTube by the Israel Defence Forces, but was later taken down for violating the site's terms of service. Jabari is the most senior Hamas operative to be killed by Israel in almost four years, since Operation Cast Lead, its three-week assault on Gaza, that left about 1400 Palestinians dead.
Thousands of people gathered in Gaza on Thursday for Jabari's funeral. His remains were being taken to the al-Omari mosque for a prayer service before his burial. High-ranking Hamas members were not expected to attend the funeral for safety reasons.
Jabari was widely believed to have been intimately involved in the Hamas takeover of Gaza in 2007, and played a key role in overseeing the imprisonment of Israeli soldier Gilad Shalit, who was snatched by Palestinian militants while on a patrol near the Gaza Strip in 2006 and held in secret locations in Gaza until his release in October 2011, in return for the release of 1027 Palestinian prisoners.
Israel's air strikes have prompted anger, fear and panic in Gaza, with residents anticipating a prolonged Israeli military campaign. Some are at shops stocking up on bread and essentials, while others are crowding outside the coastal strip's hospital and morgues.
In Australia, the Department of Foreign Affairs and Trade reissued its travel advisory for Israel and the Gaza Strip. It has not been upgraded, however it contains new information about the attacks overnight.
The Foreign Affairs Minister, Bob Carr, said the attack ''reminds us that the ultimate solution in the Middle East can only be a two-state solution, with a Palestinian state achieving the aspirations of the Palestinian people with security guarantees for Israel''.
The Opposition Leader, Tony Abbott, said: ''Israel has every right to defend itself against the threat while continuing to take every effort to avoid civilian casualties.''