Hopes for a ceasefire in Gaza between Israel and the Palestinians hung in the balance on Tuesday night after six days of violence that have claimed about 120 lives and stoked fears of a wider regional war.
Fierce fighting continued amid intense diplomacy, with wrangling and uncertainty over whether any agreement was about to take effect. Egypt and the Palestinian Islamist movement Hamas initially claimed a truce had been agreed from 7pm GMT on Tuesday, only for this to be denied by Israeli officials.
Israel on Tuesday night stepped up its bombardment with artillery shells and missiles fired from naval gunboats offshore and air strikes as Hillary Clinton, the US secretary of state, arrived in Jerusalem and held talks with Binyamin Netanyahu, the Israeli prime minister, pledging to work towards a truce in the region.
"It is essential to de-escalate the situation in Gaza. The rocket attacks from terrorist organisations inside Gaza on Israeli cities and towns must end and a broader calm restored," she said.
"The goal must be a durable outcome that promotes regional stability and advances the security and legitimate aspirations of Israelis and Palestinians alike."
Netanyahu said: "If there is a possibility of achieving a long-term solution to this problem with diplomatic means, we prefer that. But if not, I'm sure you understand that Israel will have to take whatever action is necessary to defend its people." Earlier at a press conference in Jerusalem Netanyahu said his country would be a "willing partner" in negotiations to reach a long-term ceasefire.
The public statements played out against a backdrop of ongoing violence, in what appeared to be efforts by both sides to get their last attacks in before a peace deal came into effect.
Hundreds of Palestinians fled their homes in the coastal strip after Israeli leaflets warned them to leave 11 named areas for their own safety. Heavy bursts of artillery fire were reported. Meanwhile, rockets were launched sporadically from Gaza, one hitting a building in central Israel, another landing near Jerusalem.
Mohamed Morsi, the Egyptian president, who hosted the talks in Cairo, said he expected "Israeli aggression" to cease before the end of the day.
The US increased its involvement in the negotiations. Barack Obama, returning to Washington from an Asian trip, spoke to Morsi three times in less than 24 hours, the White House said.
Both sides are under pressure to back down, with Israel being asked not to launch a large-scale ground offensive as it did in Gaza in 2008, when 1,400 Palestinians were killed.
Ban Ki-moon, the UN secretary general, urged Israel to exercise restraint. "A further escalation will be dangerous and will put the entire region at risk," he said in Jerusalem, where he held talks with leaders of both sides. "I call on everybody to restore calm. Rocket fire from Gaza on Israel is unacceptable and must stop immediately. I warn against a ground operation. We should protect civilians at all times."
Claims of a ceasefire deal emerged during a day of conflicting messages. Earlier, the Hamas military commander Mohamed Deif announced on television that his fighters were preparing for a ground war. Israeli planes dropped leaflets over a large area of the coastal enclave, warning frightened residents to evacuate.
Clinton is due to visit Ramallah early on Wednesday to meet the Palestinian president, Mahmoud Abbas, and she will then go on to Cairo. "Her visits will build on American engagement with regional leaders to support de-escalation of violence and a durable outcome that ends the rocket attacks on Israeli cities and towns and restores a broader calm," a US official said.
Morsi, a leader of Egypt's Muslim Brotherhood before he was elected president in the summer, has been at the forefront of attempts to secure a ceasefire. "The efforts to conclude a truce between the Palestinian and Israeli sides will produce positive results in the next few hours," he said. The US and Britain both praised Egypt's mediation efforts.
Ceasefire negotiations centred on Hamas's insistence that the five-year economic blockade of Gaza be lifted by the opening of the Rafah border crossing to Egypt. Israel wants a cessation of rocket fire and other attacks and insists Hamas take formal responsibility for all fire from Gaza by other factions, including Islamic Jihad.
Amid claim and counter-claim, as well as inevitable speculation and rumour, little hard detail was available about the contents of the purported agreement, but sources Sources in Cairo claimed the talks, supervised by Egyptian intelligence, would produce a two-stage solution: a cessation of violence, followed by a longer negotiated settlement over Gaza, which would require the involvement of Egypt and the US as guarantors of some kind.
Israel was reported to have rejected a Hamas demand that it pledge to refrain from "targeted assassinations" of the kind that killed the Hamas military chief Ahmed al-Jaabari at the start of this latest crisis last Wednesday. It is estimated that at least 120 Palestinians have died in the fighting since, most of them civilians, including 27 children. Three Israelis were killed last week when a rocket fired from Gaza struck their house in Kiryat Malachi. Two Israelis were reported killed , one a soldier by mortar fire on Tuesday.
Israel's leaders appear to have weighed the benefits and risks of sending tanks and infantry into the densely populated enclave two months before an election, and indicated they would prefer a diplomatic solution backed by world powers.
If a truce does take hold, there will be pressure for a renewed international diplomatic effort to ensure that the underlying issues of the conflict are resolved. An immediate issue will be the creation of an international monitoring mechanism to observe the ceasefire and report to the UN security council. Another will be the blockade of Gaza and the associated question of the network of tunnels that link southern Gaza to Egypt.
Beyond that, efforts will be needed to relaunch a long moribund peace process and promote reconciliation beteeen Hamas and the Palestine Liberation Organisation in the West Bank.