Wissam Nassar for The New York Times
JERUSALEM — After a night of ferocious airstrikes in Gaza and rocket fire toward Israel, Egypt on Friday launched a remarkable diplomatic initiative, sending its prime minister to show support for Palestinians in the beleaguered enclave, a move that prompted his Israeli counterpart to agree to a temporary cease-fire even as Israeli commanders sent armored vehicles toward the overcrowded coastal strip and called up reservists for a possible invasion.
But the frail truce did not seem to be holding, or even taking root. While news reports said the Egyptian official had arrived in Gaza, Israel Radio said Palestinian militants fired 25 rockets into southern Israel, with one rocket striking a house. There were no immediate reports of casualties. The thump of what sounded like airstrikes was also audible in Gaza City, residents said, but the Israeli military no such strikes had taken place.
Prime Minister Benjamin Netanyahu had made the temporary cease-fire by Israel’s airplanes conditional on a corresponding halt to rocket fire from Gaza.
Residents in Gaza said the night was filled with the boom and crash of airstrikes, with loud explosions at dawn on Friday, a day after Israel and the Hamas rulers of Gaza brushed aside international calls for restraint and escalated their lethal conflict. In Gaza, Palestinian militants launched hundreds of rockets into Israeli territory, targeting Tel Aviv for the first time, and Israel intensified its aerial assaults.
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.”
Within hours of the Tel Aviv air-raid warning, the Israeli Defense Forces said 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.
Early on Friday, the Israeli military said it had called up 16,000 army reservists, as preparations continued for a possible ground invasion for the second time in four years. Mr. Barak had authorized the call-up of 30,000 reservists, if needed, to move against what it considers an unacceptable security threat from smuggled rockets amassed by Hamas, the militant Islamist group that governs Gaza 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 Mr. Netanyahu said he was ready to “take whatever action is necessary.”
At the same time, though, Israel signaled its concern to preserve its so-called cold peace with Egypt, with Mr. Netanyahu agreeing to the temporary cease-fire during the visit of Prime Minister Hesham Kandil of Egypt, who planned to visit the Al Shifa hospital and meet the Hamas cabinet. For the first time since Wednesday, Ismail Haniya, the Hamas prime minister, was seen in public on Friday accompanying Mr. Kandil, Israel Radio reported.
The visit of the Egyptian delegation is expected to last about three hours, and an official in Mr. Netanyahu’s office said by telephone that Israel had told Egypt that the cease-fire would hold as long as “there would not be hostile fire from the Gaza Strip into Israel.”
“Prime Minister Netanyahu is committed to the peace treaty with Egypt,” the official said. “That peace serves the strategic interests of both countries.” There was no suggestion that the Israelis were considering a more permanent cease-fire at this stage.
Overnight, Israel said it launched 150 airstrikes while Palestinian fired a dozen rockets into Israel — far fewer than the hundreds that have hurtled toward Israel in the past two days.
President Mohamed Morsi of Egypt ordered Mr. Kandil to Gaza both as an initiative to ease the crisis and in a display of solidarity that would have been improbable in the era of President Hosni Mubarak before his overthrow last year.