Talks in Cairo aimed at securing a fresh ceasefire in Gaza are under renewed strain, with both sides in the conflict issuing warnings.
Palestinian negotiators said they would leave on Sunday if Israel did not attend without preconditions.
Israel insists it will not return until militant rocket fire ends.
Britain, France and Germany issued a statement calling on Israel and Hamas to agree a new truce, after last week’s 72-hour ceasefire was not renewed.
That ceasefire ended on Friday morning. At least eight Palestinians were killed on Saturday as Israel launched 50 airstrikes, health officials said.
Israeli authorities said 25 rockets were fired from Gaza towards southern Israel.
At least 1,960 people have died since violence erupted in Gaza in early July.
More than 1,900 Palestinians, mostly civilians, have been killed,according to the UN.
Sixty-seven people have died on the Israeli side, including three civilians.
‘Crucial 24 hours’
Israeli negotiators have already left Egypt and said they would not return to the indirect negotiations until rocket fire from Gaza stopped.
The Jerusalem Post quoted senior Israeli officials as saying that if rocket fire continued, “all options” were on the table, not just air strikes.
Communications Minister Gilad Erdan told Israel’s Channel 2 that “a wide ground incursion and the toppling of Hamas is being discussed”.
The head of the Palestinian delegation in Cairo, Azzam Ahmed, told Reuters that his team would leave on Sunday if Israel placed conditions on negotiations.
He said: “Tomorrow we have a meeting with the Egyptian leadership in the morning and on the basis of that we will decide our future plan. We will leave Cairo tomorrow if it is confirmed to us that they will not return except with conditions.”
Hamas deputy chief Mussa Abu Marzuq accused Israel of stalling and said the next 24 hours would decide the fate of the Cairo talks.
Earlier, foreign ministers Laurent Fabius of France, Philip Hammond of Britain and Frank-Walter Steinmeier of Germany said that the only way to resolve the conflict was through talks.
“We call upon all parties immediately to return to a ceasefire. We fully support the ongoing efforts by Egypt to this end” they said in a joint statement.
“To be sustainable, a ceasefire must envisage steps to address both Israeli security concerns and Palestinian requirements regarding the lifting of restrictions on Gaza,” they added.
Earlier, the US and the United Nations issues a similar call for a ceasefire.
President Barack Obama and British Prime Minister David Cameron both said Israel had the right to defend itself but urged “restraint”.
Both leaders called for an “immediate cessation of hostilities leading to a sustainable ceasefire” said a White House statement.
Hamas said Israel had failed to meet its key demands, including the lifting of the Gaza blockade and the release of prisoners. It also rejected Israel’s call for the demilitarisation of Gaza.
Tens of thousands of protesters marched through London, Paris and Cape Town in what organisers called a “Day of Rage” against Israeli military action in Gaza.
Around 150 protesters also held a demonstration in Tel Aviv despite Israeli authorities banning the gathering.
Palestinian health officials said at least seven people died in several separate airstrikes on Saturday.
Two more people died when their motorcycle was bombed, the authorities added.
Israel said it killed four Hamas militants, including one senior leader.
There have also been two major explosions in the Gaza Harbour area. A BBC correspondent says one of the blasts is believed to have targeted a Hamas training facility.
Israel said more than 70 rockets had been fired from Gaza since the end of the ceasefire.
Israel launched Operation Protective Edge on 8 July with the stated aim of halting rocket fire from militants in Gaza and destroying the network of tunnels it said were used by militants to launch attacks inside Israel.