KIRYAT MALACHI, Israel — Israel and Hamas brushed aside international calls for restraint 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 tanks rumbling toward the Gaza border for a possible invasion.
Defense Minister Ehud Barak, expressing outrage over a pair of long-range Palestinian rockets that whizzed toward Tel Aviv and triggered 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 in a pinpoint aerial bombing. But Prime Minister Benjamin Netanyahu said he was prepared to ‘‘take whatever action is necessary.’’
Although Tel Aviv was not hit Thursday and the rockets heading toward the city of 400,000 apparently fell harmlessly elsewhere, the ability of militants 40 miles away to fire those weapons 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 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 Mohammed Morsi of Egypt ordered his prime minister to lead a delegation to Gaza on Friday. In another diplomatic signal, Ban Ki-moon, the UN secretary general, also planned to visit Jerusalem, Cairo, and Ramallah, the West Bank headquarters of the Palestinian Authority, in the 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 Toner, reiterated to reporters the US position that Israel had a right to defend itself from the rocket fire and that the ‘‘onus was on Hamas’’ to stop it.
There was no sign that either side was prepared, at least not yet, to restore the uneasy truce that has mostly prevailed since the last time the Israelis invaded Gaza in the winter of 2008-09, 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 UN Security Council.’’
For his part, Netanyahu accused Hamas of placing thousands of smuggled rockets into civilian areas, including near schools and hospitals, and firing them randomly into Israel without regard to where they landed. ‘‘In the past 24 hours Israel has made it clear that it will not tolerate rocket and missile attacks on its civilians,’’ he said in a statement. ‘‘I hope that Hamas and the other terror organizations in Gaza got the message.’’
The Israel Defense Forces said that within hours of the Tel Aviv air raid warning, they had attacked 70 underground rocket-launching sites in Gaza, and ‘‘direct hits were confirmed.’’ There were also unconfirmed reports that Israeli rockets had struck near Gaza’s Rafah crossing into Egypt, forcing the Egyptians to close it.
Brigadier General Yoav Mordechai, a spokesman for the Israel Defense Forces, said its aerial assaults had hit more than 300 sites in Gaza by late Thursday, and ‘‘we’ll continue tonight and tomorrow.’’ He also said militants in Gaza had fired more than 300 rockets into southern Israel and at least 130 more had been intercepted by Israel’s Iron Dome antimissile defense system.
Southern Israel had been the target of more than 750 rockets fired from Gaza this year that hit homes and caused injuries.
Among the dozens fired Thursday was one that smashed into a four-story apartment building in Kiryat Malachi, which resulted in the first Israeli civilian deaths.
It was just after 8 a.m. when the sirens blared in Kiryat Malachi, a largely working-class town of 20,000 about 15 miles north of Gaza, which had not suffered a direct hit by rockets from Gaza before.