Wissam Nassar for The New York Times
KIRYAT MALACHI, Israel — Israel and Hamas brushed aside international calls for restraint on Thursday and escalated their lethal conflict over Gaza, where Palestinian militants launched hundreds of rockets into Israeli territory, targeting Tel Aviv for the first time, and Israel intensified its aerial assaults and sent armored vehicles rumbling toward the Gaza border for a possible invasion.
Defense Minister Ehud Barak of Israel, expressing outrage over a pair of long-range Palestinian rockets that whizzed toward Tel Aviv and set off the first air-raid warning in the Israeli metropolis since it was threatened by Iraqi Scuds in the Persian Gulf war of 1991, said, “There will be a price for that escalation that the other side will have to pay.”
He authorized the call-up of 30,000 army reservists if needed, another sign that Israel was preparing to invade Gaza for the second time in four years to crush what it considers an unacceptable security threat from smuggled rockets amassed by Hamas, the militant Islamist group that governs the isolated coastal enclave and does not recognize Israel’s right to exist.
It was not clear whether the show of Israeli force on the ground in fact portended an invasion or was meant as more of an intimidation tactic to further pressure Hamas leaders, who had all been forced into hiding on Wednesday after the Israelis killed the group’s military chief, Ahmed al-Jabari, in a pinpoint aerial bombing. But Prime Minister Benjamin Netanyahu of Israel said he was prepared to “take whatever action is necessary.”
Tel Aviv was not hit on Thursday. One rocket crashed into the sea off its coast and another apparently fell, the ability of militants 40 miles away to fire those weapons at the city of 400,000 underscored, in the Israeli government’s view, the justification for the intensive aerial assaults on hundreds of suspected rocket storage sites and other targets in Gaza.
Health officials in Gaza said at least 19 people, including five children and a pregnant teenager, had been killed over two days of nearly nonstop aerial attacks by Israel, and dozens had been wounded. Three Israelis were killed on Thursday in Kiryat Malachi, this small southern Israeli town, when a rocket fired from Gaza struck their apartment house.
In a sign of solidarity with Hamas as well as a diplomatic move to ease the crisis, President Mohamed Morsi of Egypt ordered his prime minister to lead a delegation to Gaza on Friday. In another diplomatic signal, Ban Ki-moon, the United Nations secretary general, also planned to visit Jerusalem, Cairo and Ramallah, the West Bank headquarters of the Palestinian Authority, in coming days.
In Washington, Obama administration officials said they had asked friendly Arab countries with ties to Hamas, which the United States and Israel regard as a terrorist group, to use their influence to seek a way to defuse the hostilities. At the same time, however, a State Department spokesman, Mark C. Toner, reiterated to reporters the American position that Israel had a right to defend itself from the rocket fire and that the “onus was on Hamas” to stop it.
The Pentagon said late Thursday that Defense Secretary Leon E. Panetta spoke to Mr. Barak this week about Israeli operations in and around Gaza and condemned the violence carried out by Hamas and other groups against Israel.
There was no sign that either side was prepared, at least not yet, to restore the uneasy truce that was forged the last time the Israelis invaded Gaza in the winter of 2008-9, a three-week war that left 1,400 Palestinians dead and drew widespread international condemnation.
Denunciations of Israel for what critics called a renewal of its aggressive and disproportionate attacks spread quickly on the second day of the aerial assaults. The biggest criticism came from the 120-nation Nonaligned Movement, the largest bloc at the United Nations. In a statement released by Iran, which holds the group’s rotating presidency and is one of Israel’s most ardent foes, the group said: “Israel, the occupying power, is, once more, escalating its military campaign against the Palestinian people, particularly in the Gaza Strip.” The group made no mention of the Palestinian rocket fire aimed at Israel but condemned “this act of aggression by the Israelis and their resort to force against the defenseless people” and demanded “decisive action by the U.N. Security Council.”