GAZA CITY, Gaza Strip — Israel carried out a blistering offensive of more than 20 airstrikes in the Gaza Strip on Wednesday, assassinating Hamas' military commander and targeting the armed group's training facilities and rocket launchers. It was Israel's most intense attack on the territory in nearly four years.
Israel said the airstrikes, launched in response to days of rocket fire out of Hamas-ruled Gaza, were the beginning of a broader operation against the Islamic militants code-named "Pillar of Defense." Israeli defense officials said a ground operation was a strong possibility in the coming days though they stressed no decisions had been made and much would depend on Hamas' reaction. There were no immediate signs of extraordinary troop deployments along the border.
The attack came at a time when Israel seems to be under fire from all directions. Relations have been deteriorating with Egypt's new Islamist government, Egypt's lawless Sinai desert has become a staging ground for militant attacks on Israel, and the Syrian civil war has begun to spill over Israel's northern border. Earlier this week, Israel fired back at Syria — for the first time in nearly 40 years — after stray mortar fire landed in the Israeli-controlled Golan Heights.
With at least 10 Palestinians dead, including two young children, Wednesday's offensive was certain to set off a new round of heavy fighting with Gaza militants, who have built up a formidable arsenal of rockets and missiles.
It also threatened to upset Israel's relations with neighboring Egypt and shake up the campaign for Israeli elections in January. In a preliminary response, Egypt recalled its ambassador to Israel in protest.
President Barack Obama spoke with Israeli Prime Minister Benjamin Netanyahu and Egyptian President Mohammed Morsi on Wednesday night about rocket attacks being launched from Gaza into Israel and escalating violence in the Gaza Strip.
The White House said Obama reiterated U.S. support for Israel's right to self-defense from rocket attacks being launched against its civilians and urged Israel to "make every effort to avoid civilian casualties" in its response.
In a nationwide address, Netanyahu said Israel could no longer stand repeated attacks on its southern towns. Days of rocket fire have heavily disrupted life for some 1 million people in the region, canceling school and forcing residents to remain indoors.
"If there is a need, the military is prepared to expand the operation. We will continue to do everything to protect our citizens," Netanyahu declared.
The Israeli military said it was ready, if necessary, to send ground troops into Gaza. The defense officials who said a ground operation was likely in the coming days spoke on condition of anonymity because they were discussing sensitive military plans.
"We are at the beginning of the event, and not the end," Defense Minister Ehud Barak said, in a joint appearance with the prime minister. "In the long run I believe the operation will help strengthen the power of deterrence and to return quiet to the south."
Residents in both Israel and Gaza braced for prolonged violence. Gazans rushed to stock up on food and fuel. After nightfall, streets were empty as the sounds of Israeli warplanes and explosions of airstrikes could be heard in the distance.
The deadly attack on Hamas mastermind Ahmed Jabari marked the resumption of Israel's policy of "targeted killings," or assassinations of senior Hamas men. Israel has refrained from such attacks, which have drawn international condemnations, since a fierce three-week offensive in Gaza that ended in January 2009.
Jabari was the most senior Hamas official to be killed since that war. He had long topped Israel's most-wanted list, blamed for masterminding a string of deadly attacks that including a bold, cross-border kidnapping of an Israeli soldier in 2006. He also was believed to be a key player in Hamas' takeover of Gaza in 2007 from a rival Palestinian faction, the Western-backed Fatah movement.
"I would call him the No. 1 terrorist in the Gaza Strip, whose hands are stained with blood," said Brig. Gen. Yoav Mordechai, Israel's chief military spokesman.
The Jabari killing, carried out in broad daylight, was shocking. Hamas officials had brushed off the Israeli threats, illustrated by Jabari's decision to drive in public. Hamas leaders typically go into hiding at times of rising tensions. Over the past two days, the fighting had shown signs of abating as Egyptian mediators tried to broker a truce.
The Israeli military released a black-and-white video of the airstrike, showing a sedan moving slowly along a road before going up in flames in an explosion so powerful that a large chunk of the vehicle flew high into the air.
Hamas announced a state of emergency in Gaza. Outside the hospital where Jabari's body was taken, thousands of Gazans chanted "Retaliation!" and "We want you to hit Tel Aviv tonight!"
In a statement, Hamas' prime minister, Ismail Haniyeh, eulogized Jabari and vowed revenge.
"We mourn our late leader who walked the path of jihad while he knew the end, either victory or martyrdom," Haniyeh said. "There is no fear among our people and our resistance, and we will face this vicious attack."