GAZA CITY, Gaza Strip (AP) -- Palestinian militants barraged Israel with more than 200 rockets on Thursday, killing three people as Israel pressed a punishing campaign of airstrikes on militant targets across the Gaza Strip. Three rockets targeted the densely populated Tel Aviv area, setting off air raid sirens in brazen attacks that threatened to trigger an Israeli ground invasion of Gaza.
Late in the day, Israel signaled a ground operation may be imminent as forces moved toward the border area with Gaza. At least 12 trucks were seen transporting tanks and armored personnel carriers, and a number of buses carrying soldiers arrived. Israeli Defense Minister Ehud Barak said he had authorized the army to call-up additional reservists for possible action. The army said it was prepared to draft up to 30,000 additional troops.
"I ordered the military today to widen the draft of reserve soldiers in order to be able to be ready for any development," Barak said. Military officials said the moves were to prepare for the possibility of a ground invasion, but stressed no decision had been made. Israel TV stations, however, said a ground offensive was expected Friday.
The fighting, the heaviest in four years, has also killed 15 Palestinians in two days and brought life to a standstill on both sides of the border. School has been canceled and many were huddling indoors.
Israel and Hamas have largely observed an informal truce for the past four years. But in recent weeks, the calm unraveled in a bout of rocket attacks on Israel from Gaza and retaliatory Israeli airstrikes.
The fighting showed no signs of slowing after dark. Israeli aircraft carried out dozens of attacks on militant targets in Gaza, while militants fired barrages of rockets throughout the day. The fighting began on Wednesday after Israel killed Hamas military chief Ahmed Jabari in an airstrike, then attacked dozens of rocket launchers. The offensive follows weeks of rocket fire out of Gaza.
Thursday's attacks on Tel Aviv, some of the deepest rocket strikes from Gaza on record, set air raid sirens blaring and sparked panic in the streets of the normally laid-back commercial and cultural capital. Israeli Channel 2 TV showed panicked Tel Aviv residents running for cover and lying down on the ground after the sirens began wailing. Diners hid under tables in a restaurant, and traffic snarled on the city's main north-south highway. There were no injuries.
Workers and visitors at offices in a Tel Aviv skyscraper froze for a few seconds in silence as the sound of the sirens wafted through the open windows.
Some murmured "I don't believe it," but everyone quickly and calmly rose and walked to the stairwell to go down to the building's bomb shelter. Many reached for their mobile phones to call loved ones and urge them to run to a protected space, while others kept dialing in frustration as cell networks were overloaded.
One of the rockets landed in an open area of Rishon Lezion, a city on Tel Aviv's southern outskirts, while police said the other two appeared to have landed in the sea. Although there were no injuries, Israel considers any attempt to disrupt life in Tel Aviv to be a major escalation.
Defense officials say Israel is prepared to launch a ground invasion into Gaza if necessary. And Prime Minister Benjamin Netanyahu said the army was prepared for a "significant widening" of its Gaza offensive.
"No government would tolerate a situation where nearly a fifth of its people live under a constant barrage of rockets and missile fire, and Israel will not tolerate this situation," he said. "This is why my government has instructed the Israeli Defense Forces to conduct surgical strikes against the terrorist infrastructure in Gaza. And this is why Israel will continue to take whatever action is necessary to defend our people."
Hamas Prime Minister Ismail Haniyeh eulogized Jabari in a televised speech on Thursday night.
"What a martyrdom and what a glorious day," he said. "Congratulations. Rest in peace. Feel blessed."
He said Palestinians remained steadfast and defiant during the 22 days of the last Gaza war in 2009 and could hold out for even longer.
"Years after that war, we emphasize that Palestinians are prepared to stand steadfast longer than that," he said. "It is resistance that is capable of creating a new equation on the ground ... capable of fending off aggression and taking revenge for the noble blood of those who have fallen."
Israeli officials say they have not yet decided on whether to launch a ground invasion in Gaza.