US Secretary of State John Kerry on Tuesday again placed the onus on Hamas to accept a ceasefire along the lines of an Egyptian proposal to end the conflict raging in Gaza.
The top US diplomat was speaking in Cairo after meeting Egyptian President Abdel Fattah al-Sisi, whose government's ceasefire proposal last week was accepted by Israel but rejected by Hamas, the main power in Gaza.
Kerry voiced support for the initiative as a "framework" to end violence that has killed almost 600 Palestinians and 29 Israelis in two weeks of fighting.
But Hamas, which has been relentlessly firing rockets into Israel, insists the Jewish state lift its eight-year blockade of Gaza before it agrees a truce.
"While we still have work to do, it is clear to each party I met that there is a framework available to end the violence, and that framework was the Egyptian initiative," Kerry said at a press conference after meeting Sisi.
He indicated he would hold further meetings to address the root causes of the conflict, but did not elaborate.
He would, he said, meet "into the next days in order to work to see if we can find a way forward that ends the violence and then addresses the underlying causes of this crisis."
Egypt, which shares a border with Gaza and Israel, has brokered truces in past conflicts but has had less sway over Hamas after blacklisting the militant movement earlier this year.
The government accuses it of aiding Egypt's Muslim Brotherhood, which Sisi overthrew last year.
Kerry, who has invested much of his tenure in an unsuccessful bid for a lasting Middle East peace agreement, again placed the blame for the latest conflict on Hamas.
"For two weeks now, we have seen Hamas launch rocket after rocket at Israeli neighbourhoods," he said.
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"Israel responded as any country has the right to do when it is under attack."
- 'Fundamental choice to make' -
"Hamas has a fundamental choice to make," he added.
A senior Israeli minister on Tuesday said her government would not agree to Hamas's "unacceptable" demands and would end its operations once it destroys tunnels used by Hamas infiltrators for attacks in Israel.
"First of all, it won't happen before we really finish the tunnels project which was laid out as a strategic objective," Justice Minister Tzipi Livni told the Israeli Ynet news website.
Egyptian officials have publicly ruled out amending their proposal, which calls for a ceasefire first and negotiations later.
US officials said they were also looking to see if they could encourage changes in Egypt's proposal to secure the backing of Hamas, which believes Israel has reneged on previous agreements.
"It's going to require conversations with both parties on the ground before we really know what exactly a ceasefire that can work is going to look like," the official said.
Kerry met early in the morning with the Palestinian Authority's intelligence chief, Majid Faraj, a US official said.
Kerry also went to the headquarters of the Arab League to consult with the bloc's chief Nabil al-Arabi, who described the killings of Palestinians as a "massacre" and urged a broader agreement.
"What is needed is that all hostile acts should end as soon as possible," Arabi said.