A ceasefire between Israel and armed groups in Gaza depends on each side's ability to claim victory and the credibility of the mediation, undermined by Israel launching strikes with a truce already in effect.
Incessant Israeli air raids and Palestinian rocket attacks, which began Wednesday when Israel assassinated a senior Hamas militant, showed no signs of abating on Sunday.
Meanwhile, diplomatic contacts took place, primarily in Cairo, in a bid for a cessation to the hostilities.
Egypt's President Mohamed Morsi said he was optimistic "there could be a ceasefire soon," in remarks at a joint news conference on Saturday night with Turkish Prime Minister Recep Tayyip Erdogan.
Exiled Hamas leader Khaled Meshaal discussed a truce with the head of Egyptian intelligence, Erdogan and Qatari Emir Hamad bin Khalifa al-Thani, demanding international guarantees for a ceasefire with Israel.
Hamas official Yussef Ahmad told the Palestinian Authority's official radio station Voice of Palestine that his movement demanded that "the unjust siege" of Gaza be lifted by Israel.
This was "in addition to halting the frequent Israeli aggression and assassinations" as another condition for an agreement, he said.
Analysts in Israel say the Jewish state's leadership appears satisfied with the success of Operation Pillar of Defence, and that it could be ready for a ceasefire.
"Over the weekend the Israeli army looked at the first four days of the operation and was satisfied with the results," military analyst Amir Rapaport wrote in Maariv newspaper.
"After the army managed to stun Hamas with the opening move of assassinating the head of the organisation’s military branch, Ahmad Jaabari, efforts over the weekend focused on preserving the deterrence created by the assassination.
"The ball has been in the political echelon’s court since yesterday, and it will decide between moving ahead with the ceasefire talks and the option of a ground operation," he wrote on Sunday.
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According to the military correspondent at Yediot Aharonot newspaper, nobody within the group leading the operation is "pushing or eager for" a ground incursion.
"But if Hamas manages to inflict dramatic harm to Israel in order to get a 'victory picture,' there is a viable concern that the cabinet ministers won’t withstand the temptation to 'rectify' the impression this picture would leave on the Israeli voter," wrote Alex Fishman.
Israel is scheduled to hold a general election on January 22.
In a broadcast Saturday night on Hamas television, the Islamist movement's armed wing, the Ezzedine al-Qassam Brigades, boasted its success in the confrontation.
"Israel's main goal is to ensure long-term quiet, to obtain a promise to prevent Palestinian attacks on Israeli communities and on Israeli army patrols along both sides of the border fence," analysts Amos Harel and Avi Issacharoff wrote in Haaretz.
"One of the difficulties at the moment in reaching an agreement involves the lack of a sufficiently dominant broker to clinch the deal."
A senior Hamas official said on Saturday that "Egypt cannot say any more: 'I guarantee a truce.'"
"Through Egyptian mediation, we reached an understanding for a truce and it was broken in about 48 hours," the official said on condition of anonymity.
The Israeli air strike that killed the Hamas military chief on Wednesday occurred during a lull after a three-day confrontation.
Erdogan also charged on Saturday that "it is Israel that violated the ceasefire" and was responsible for the escalation.
Egypt, led by Islamist President Morsi, has been pressed, meanwhile, to exert its influence on Hamas to restore calm.
"Israel should abide by its commitments and the agreements it has signed" Egyptian Prime Minister Hisham Qandil said during a visit to Gaza on Friday as he vowed to "intensify efforts" for a truce.