Gaza City, Palestinian Territories - Israeli war planes pounded Gaza with more than 50 strikes on Tuesday at the start of a new military campaign to stamp out rocket fire by Hamas militants on southern Israel.
It was the most serious flare-up in and around the territory since November 2012 and came as Israel struggled to contain a wave of violence in Arab towns over the grisly murder of a Palestinian teenager by Jewish extremists.
Palestinian president Mahmud Abbas demanded Israel "immediately stop" its air campaign, dubbed Operation Protective Edge, and asked the international community put pressure on the government of Prime Minister Benjamin Netanyahu.
But Netanyahu was set to hold talks with security chiefs later on Tuesday at which he was expected to order a "significant broadening" of the operation and instruct the military to "take off the gloves," a source close to the him told public radio.
After nearly four weeks of restraint in the face of intensifying rocket fire on the south, Israel appeared bent on dealing the Islamist Hamas movement a heavy blow, with officials speaking of a "staged escalation"..
320 rockets fired
In Gaza, medics said seven children and three women were among 22 people wounded in the overnight strikes, with more raids during the morning. Two of the wounded were in serious condition.
The Israeli army said the air force and the navy had struck around 50 "terror sites" overnight in a joint operation which had three aims - returning calm to the south, "eliminating Hamas's capabilities and destroying the terror infrastructure" in Gaza.
It also destroyed the homes of four militants from Hamas's armed wing, the Ezzedine al-Qassam Brigades, it said were responsible for rocket fire.
Since 12 June, when the current round of tit-for-tat violence began, Gaza militants have fired more than 320 rockets over the border, with 250 of them hitting Israeli territory and another 40 intercepted by the Iron Dome air defence system.
So far there have been no Israelis killed.
In the past 12 hours, militants have fired at least 26 rockets at southern Israel, an army spokesperson said.
The education ministry cancelled all summer schools and camps within a 40 kilometre radius of Gaza, except those being held in protected spaces, army radio reported. A staged operation
"We acted forcefully overnight and will continue to do so in the coming days," military spokesperson General Moti Almoz told the radio, saying the operation would take place "in stages".
"We have been instructed by the political echelon to hit Hamas hard."
He said Israel was also preparing for the possibility of a ground offensive.
"All options are on the table, all these steps are being considered," he said.
"Two brigades, which are currently stationed around the Gaza Strip, are prepared and ready, and in the coming days, more will arrive," he added.
The decision to hit Gaza was taken at a meeting of the security cabinet on Monday afternoon, which approved a "staged escalation" whereby pressure on Hamas would be stepped up with every passing day, the radio said.
Defence Minister Moshe Yaalon warned it was likely to be a protracted campaign.
"We are preparing for a campaign against Hamas, which will not end in just a few days," he said.
"In the last few hours, we hit forcefully and damaged dozens of Hamas assets and the IDF will continue its offensive efforts to exact a very heavy price from Hamas," he said, warning that Israel was preparing "to broaden the campaign with all available means."
Israel's Channel 1 television on Monday showed footage of dozens of tanks massing near the border, preparing for a possible offensive. Possible ground assault
Reports said Netanyahu had ordered the military to prepare for a possible ground assault.
"The prime minister has ordered the army to be ready to go to the end. A ground offensive is the option which is on the table," a senior official told the website of Haaretz newspaper.
"We have to hit Hamas because our power of deterrence has been reduced," Interior Minister Gideon Saar told public radio.
"No one is enthusiastic about the idea of a military confrontation, but we cannot hesitate any more.
"We cannot restore the calm without proving to Hamas that it is absolutely in its interest to halt attacks on Israel, but to do that, we must hit it sufficiently hard."
The latest flare-up comes as Israel arrested six Jewish extremists in connection with the grisly kidnap and murder of the Palestinian teenager, who was burned alive in a suspected revenge attack the killing of three Israeli youths in the occupied West Bank.
Three of them have confessed, an official close to the investigation told AFP.
The killing sparked five days of violent clashes between angry protesters and riot police in annexed east Jerusalem and Arab towns across Israel.
Police arrested another 39 people overnight, raising the overall number of people detained to 299.