BBC's Jeremy Bowen: "Civilians on both sides need a ceasefire"
At least 105 people have died in the Gaza Strip in six days of violence, Hamas officials say, as Israeli forces continue their bombardment.
Monday's fatalities include a commander of the Islamic Jihad militant group and a couple and their two small children.
More than 100 rockets were fired on Israel on Monday, but no casualties were reported. Last week, three Israelis died in one such attack.
The Israeli cabinet has been meeting to discuss an Egyptian ceasefire proposal.
The content of the Egyptian plan is not known, but both Israel and Hamas have presented conditions.
Israel's include no hostile fire of any kind from Gaza and international efforts to prevent Hamas from rearming, while Hamas is demanding an end to the blockade on Gaza and "Israel's assassinations".
Egypt has been leading efforts to broker a peace deal, with both senior Israeli and Hamas officials in Cairo for talks. An Egyptian official said he hoped to be able to make an announcement on Monday or Tuesday.
Uzi Landau, Israeli cabinet minister: Country forced to the point of war by "continued bombardment" from Gaza
UN Secretary-General Ban Ki-moon has also arrived in Cairo to aid negotiating efforts. He plans to meet Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas in the coming days.
US President Obama spoke to his Egyptian counterpart Mohamed Mursi and to Mr Netanyahu on Monday and "discussed ways to de-escalate the situation in Gaza," the White House said in a statement.
Mr Obama "underscored the necessity of Hamas ending rocket fire into Israel" in his call to Mr Mursi, and "expressed regret for the loss of Israeli and Palestinian civilian lives" in both calls.
Russian UN Ambassador Vitaly Churkin said Moscow might propose a Security Council resolution calling for an end to violence on both sides.
He said that an unnamed Security Council member, apparently the US, was delaying Arab attempts to adopt a lower-level statement on the crisis.
'Terrorist state'Khaled Meshaal, the political leader of the Islamist movement Hamas which controls Gaza, said earlier that a truce was possible in Gaza - as was further escalation of the conflict.
"We are for a ceasefire," Mr Meshaal said, "but Israel must stop its aggression."
Meanwhile, Turkish Prime Minister Recep Tayyip Erdogan described Israel as a "terrorist state", citing the "massacre of children" during its bombardments of Gaza.
Once cordial relations between Turkey and Israel soured after Israeli marines stormed a Turkish aid ship in 2010 during a naval blockade of Gaza.
Hamas officials gave details of several fatalities during Monday afternoon which pushed the Palestinian death toll above 100.
Analysis
In truth there is little enthusiasm in Israel - either in the government or among the military top brass - for a ground incursion into the Gaza Strip.
Israeli military analysts believe that a large part of Israel's military goals were achieved during the opening two days of this conflict.
As the air campaign goes on, Israel faces diminishing returns.
The increase in the number of civilian casualties inflicted in the Gaza Strip, and the consequent shift in international support for Israel, probably weighs more heavily than any modest advantages in terms of destroying additional rockets or Hamas infrastructure.
A leading figure in the militant group Islamic Jihad, named as Ramez Harb, was killed as a building housing media workers was struck.
Later, a couple and two children aged two and four were killed in an air strike on Beit Lahiya, Gaza's health ministry said.
Six others were killed in four separate attacks, AFP quoted emergency services as saying, and four people died of injuries sustained on Sunday.
A Palestinian youth was killed in the southern West Bank town of Hebron, apparently after protests against the attacks in Gaza, reports say.
At least nine children were killed in Gaza on Sunday - the bloodiest day so far - and TV reports showing images of their burned and bloodied bodies have been fuelling Palestinian anger, says the BBC's Jon Donnison in Gaza City. In one strike, nine members of the family of Hamas policeman Mohamed Dalou were killed - four of them children.
The army's chief military spokesman, Yoav Mordechai, told Israel's Channel 2 TV that the intended target of the strike had been Yehiya Rabiyah, the head of Hamas's rocket-launching unit, but admitted that there had been civilian casualties.
Later, the IDF told the BBC that the house had been targeted because it was thought Mr Rabiyah might be hiding there, but officials did not know whether he was inside at the time of the attack.
War or peace?Mr Netanyahu said on Sunday that he was ready to expand the operation, after Israel authorised the mobilisation of up to 75,000 army reservists.
Since the conflict began, 877 rockets have been fired towards Israel, the IDF says, with 570 landing in Israel and 307 intercepted by the Iron Dome missile defence system.
Before the recent offensive, Israel had repeatedly carried out air strikes on Gaza as Palestinian militants fired rockets across the border.
But the aerial and naval bombardment is its most intense assault on the territory since Israel launched a full-scale invasion four years ago.
Hamas seized control of Gaza in 2007, a year after winning a decisive victory in general elections. Israel withdrew from the strip in 2005 but maintains a blockade around it.
Israel, as well as the United States and the European Union, regards Hamas as a terrorist organisation.
Tel Aviv, Israel
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Ashkelon, Israel
Ashkelon bears the brunt of rocket attacks on Israel
Jabaliya refugee camp
A man surveys the rubble of a house in Jabaliya refugee camp
Gaza City
The homes of at least seven Hamas officials hit in Israeli attacks on Gaza City
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