JERUSALEM: Israel has launched multiple airstrikes in the Gaza Strip, killing seven Palestinians, while militants fired more than 100 rockets and mortars into southern Israel in what threatens to develop into a major confrontation.
Israel also confirmed on Sunday it had fired a series of warning shots into Syria, after one of its military posts in the occupied Golan Heights was hit with mortar fire from across the border.
"The world needs to understand that Israel will not sit idly by in the face of attempts to attack us"
The latest escalation began when a tunnel packed with explosives under the Gaza-Israel border blew up late on Thursday in what an Israeli military spokeswoman, Lieutenant-Colonel Avital Leibovich, described as an attempt to kidnap or kill soldiers.
In the cycle of violence that followed, Israeli airstrikes killed at least seven Palestinians and wounded more than 50, rockets and mortars fired from Gaza injured four Israeli civilians and an attack on an Israeli military jeep left four soldiers wounded, one critically.
After 72 hours of hostilities, Israel's Prime Minister, Benjamin Netanyahu, said his country was "prepared to intensify" its response.
"The IDF is operating, and will operate, aggressively against the terrorist organisations in the Gaza Strip, which are taking heavy blows from the IDF," Mr Netanyahu said following the government's weekly cabinet meeting.
"The world needs to understand that Israel will not sit idly by in the face of attempts to attack us."
Among the Palestinian fatalities were five civilians, including three children, the Gaza-based Palestinian Centre for Human Rights said.
"Four of these deaths and 38 of the injuries resulted from an Israeli attack on a football playground in al-Shoja'iya neighbourhood east of Gaza City," the centre said.
Three shells fired by the IDF hit a house, killing another two civilians, the centre said, while in separate attacks two militants were killed, businesses were damaged and a number of homes destroyed.
Earlier on Thursday evening, the centre said, Israeli forces killed a 13-year-old Palestinian, Ahmed Younis Khader Abu Daqqa, who was shot while playing football with friends in front of his house in Abassan, near the southern Gaza town of Khan Yunis.
Rockets fired by militants in Gaza landed in the southern Israeli cities of Ashdod and Ashkelon, as well as in the Eshkol Regional Council and Sha'ar HaNegev Regional Council and in Gan Yavne, the Israeli Government confirmed.
Schools were closed throughout Gaza and southern Israel in response to the escalation in violence. Most rockets fired from Gaza landed in open fields.
Islamic Jihad and the Popular Front took responsibility for the rocket fire, although the IDF says Hamas is the only party responsible for the escalation in southern Israel.
A spokesman for Hamas militants threatened further action in response to Israel's attacks, Associated Press reported.
"Targeting civilians is a dangerous escalation that cannot be tolerated. The resistance has the full right to respond to the Israeli crimes," Fawzi Barhoum said.
With an election due on January 22, Israeli politicians were quick to demand harsh retribution against Gaza.
The Transport Minister, Yisrael Katz, told Sunday's cabinet meeting that Israel should completely cut itself off from Gaza, end the supply of electricity, water, food and gas to Gaza residents and "take out the leadership of Hamas in Gaza".
The Homefront Defence Minister, Avi Dichter, told the Hayom newspaper the elections would not preclude the possibility of an extensive military operation in Gaza.
"There was already action taken once before, a month ahead of the elections," Mr Dichter said, referring to Operation Cast Lead, the Israeli assault on Gaza in December 2008 and January 2009 in which 1400 Palestinians were killed. "Anyone who thinks that this is a protective barrier will be surprised."
The mortar fire on the Syrian border was ‘‘part of the internal conflict inside Syria’’ and caused no injuries, a statement posted on the Israel Defence Force site said.
‘‘The IDF has filed a complaint through the UN forces operating in the area, stating that fire emanating from Syria into Israel will not be tolerated and shall be responded to with severity,’’ the statement said.
Israel has not fired at Syria since the 1973 Yom Kippur War, although the two countries are technically in a state of war and the United Nations patrols the demilitarised buffer zone along their shared border.
Last week the IDF reported that three Syrian tanks had entered the buffer zone, while on two other occasions – July 29 and September 25 – Syrian forces entered the buffer zone and fired mortars into the area.
‘‘This is a Syrian issue that could become our issue,’’ the Chief of Staff, Lieutenant-General Benny Gantz, said, confirming that troops had been put on high alert to prevent the violence spilling over the border.
The Prime Minister, Benjamin Netanyahu, said Israel was closely monitoring the border and was ‘‘ready for any development’’.