Efforts to agree a ceasefire between Israel and the Palestinians are to intensify, with the UN chief, Ban Ki-moon, weighing in amid guarded optimism that a deal is possible because it suits both sides to end the fighting.
On a sixth day of Israeli attacks in the Gaza Strip and sporadic though decreasing Palestinian rocket fire into Israel, negotiations in Cairo focused on securing a package that would allow both warring parties to claim some kind of victory.
Barack Obama discussed the crisis in a phone call to the Egyptian president, Mohamed Morsi, on Monday, while William Hague, Britain's foreign secretary, paid tribute to Egypt's efforts to negotiate "a ceasefire that can work".
Jay Carney, the White House press secretary, said Obama and Morsi "discussed ways to de-escalate the situation in Gaza", and Obama "underscored the necessity" of Hamas ending rocket fire into Israel.
"President Obama then called prime minister [Binyamin] Netanyahu of Israel, and received an update on the situation in Gaza and Israel," Carney added. "In both calls, President Obama expressed regret for the loss of Israeli and Palestinian civilian lives, and agreed to stay in close touch with both leaders."
Ban arrived in Cairo amid growing international concern that the crisis could escalate and spread. Israel is under pressure to refrain from sending ground forces into the heavily-populated coastal strip in the wake of its six-day air and naval assault.
The UN secretary-general will visit Jerusalem for talks with Netanyahu on Tuesday, before heading to the West Bank town of Ramallah to see the Palestinian president Mahmoud Abbas.
Khaled Meshal, the Hamas leader, told reporters in Cairo that Israel must be the first to halt military operations since it had begun them last week by assassinating the movement's military chief, Ahmed al-Jabari. "A ground invasion will not be a walk in the park," Meshal warned. "We don't have the same military and deterrence capabilities [as Israel] but we have deterred them with our will. Our enemy is drowning in the blood of children."
Dan Harel, a former deputy chief of staff of the Israeli army, said: "We are moving straight into a T-junction. There are two basic alternatives. The first is an agreement cooked in Cairo. The second is an escalating situation, moving into the Gaza Strip with a land [invasion] which will be bad for both sides. We are 24 to 48 hours from this junction."
Officials in Jerusalem flatly denied Meshal's claim that Israel was seeking a ceasefire. It was Hamas, one official said, that was looking for a way to "climb down" after more than 400 air strikes in Gaza had significantly eroded the Palestinians' ability to launch missiles at Tel Aviv and other Israeli cities.
"Hamas's comments about a ceasefire, alleging that Israel is begging for one, are about as accurate as its claims to have shot down an F-15 [warplane] or attacked the Knesset," Reuters quoted a unnamed senior government official as saying.
Israeli officials also emphasised their readiness to launch a ground offensive, although there were reports of complaints from Israeli army reservists that they were wasting their time. The US, Britain and other western governments have urged Israel not to mount an assault like Operation Cast Lead, in which 1400 Palestinians in Gaza were killed four years ago.
Diplomats in Jerusalem and Tel Aviv were hopeful that a deal could yet be forged. "The fact that the talks are still going on is a good sign," said one. "And the fact that Israel hasn't yet gone in on the ground is a good sign."
The Cairo truce talks ran into trouble on Sunday after news that 10 members of one family had been killed in Gaza in an air strike apparently aimed at killing a Hamas or Islamic Jihad leader.
British officials monitoring the crisis said the key was to de-escalate, secure a durable ceasefire, and then return to the key questions of promoting reconciliation between Hamas and the PLO and re-invigorating a moribund peace process.
Hague said in Brussels: "I am pleased that Israel has held back from a ground invasion while such negotiations go on, and that the rate of rocket attacks on Israel has fallen, for whatever reason, over the last 24 hours. These are positive developments, but of course it remains a desperately serious and difficult situation."
Palestinian sources said that Abbas had responded angrily on Monday to Tony Blair, the Middle East Quartet's envoy, in a meeting in Ramallah. Blair is trying to persuade Abbas to refrain from seeking observer status at the UN – a move opposed by the US and Israel. Abbas reportedly told him to leave if he was not there to talk about the crisis in Gaza.
Israeli sources made clear that a ceasefire deal would have to mean an end to all hostile fire from Gaza into Israel, including small arms fire at troops near the border. Hamas fighters must also be stopped from crossing into Sinai to mount attacks against Israel from Egyptian territory. Hamas must not be allowed to rearm. Any ceasefire must not be a simple "time out" for Hamas but provide an extended period of quiet for southern Israel.
Support for Operation Defensive Pillar remains solid in Israel. According to an opinion poll in Haaretz, 30% of the Israeli public support a ground invasion despite the risks of high casualties. Overall the operation has the backing of around 84% of the public, with 12% opposed.
But in one sign of dissent, 100 writers, intellectuals and artists on Monday issued a petition calling for a long-term ceasefire, and more significantly for talks with Hamas, which has long been a political taboo. "We must speak out because the people of southern Israel, like the people of Gaza, deserve to be able to look up at the sky in hope and not in fear, wrote the author Amos Oz, playwright Yehoshua Sobol and others.
Additional reporting by Abdel-Rahman Hussein in Cairo
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