Israel (BBN)-Israel has resumed its air strikes on Hamas-controlled Gaza, after Israel's brief truce was met with continuing rocket fire.
Israel had earlier accepted an Egyptian ceasefire proposal and halted operations on Tuesday morning, reports BBC.
But the armed wing of Hamas rejected the initiative as a "surrender".
Palestinian officials say at least 192 people have been killed by Israeli air strikes launched eight days ago to stop militants firing rockets into Israel.
At least four Israelis have been seriously injured since the violence flared, but none have been killed.
The Israel Defense Forces said about 50 rockets had been fired into Israel during the six hours it had halted air strikes on Tuesday.
It took six hours for the first attempt to broker a deal between Israel and Hamas to founder.
Israeli PM Benjamin Netanyahu had warned that if the rocket fire continued, Israel would hit back hard – and now it has.
In the search for a ceasefire, this is clearly a setback although not necessarily a terminal blow.
Hamas wants some concessions – like the lifting of the tight restrictions Israel and Egypt impose on Gaza's border – in advance of any deal.
Egypt won't give up on its diplomatic efforts after a single setback but the resumption of hostilities means the question of whether Israel will eventually order ground operations is back on the agenda.
A number of new targets in Gaza have now been hit by Israeli air strikes.
Under the terms of the Egyptian initiative, the ceasefire should have been followed by a series of meetings in Cairo with high-level delegations from the two sides.
There has been no definitive response to the initiative from Hamas.
PM Benjamin Netanyahu (speaking before operations resumed): "Our goal remains putting an end to rocket fire from Gaza"
Senior Hamas spokesman Osama Hamdan told the BBC it had only heard about the truce initiative through the media and that a ceasefire could not be put in place without the details of any agreement being known.
The armed wing of Hamas, the Izz al-Din Qassam Brigades, dismissed the initiative, saying its battle with Israel would "increase in ferocity and intensity".
US Secretary of State John Kerry said he could not "condemn strongly enough" Hamas' actions in continuing to fire rockets.
Israeli government spokesman Mark Regev told the BBC: "Hamas had seven hours to get their act together and they have rejected this ceasefire proposal… it's rejected it both in word and in deed."
Israel's security cabinet, convened by Prime Minister Benjamin Netanyahu, had approved the truce on Tuesday morning, minutes before the proposed time for it to come into effect – at 09:00 (06:00 GMT).
"We agreed to the Egyptian proposal in order to give an opportunity for the demilitarisation of the [Gaza] Strip – from missiles, from rockets and from tunnels – through diplomatic means," Netanyahu had said.
But he had then added: "If Hamas does not accept the ceasefire proposal, as would now seem to be the case, Israel would have all international legitimacy to broaden the military operation to achieve the required quiet."
The BBC's Kevin Connolly said that Israel's rapid acceptance of the Egyptian ceasefire proposal was a smart tactical move.
If the deal had held, Israel would have been happy with the outcome, he says, because it has damaged stockpiles of weapons that Hamas will find difficult to replenish.