At least 393 Palestinians, including dozens of civilians, have been killed and about 1,600 injured as Israeli warplanes and helicopter gunships have dropped hundreds of bombs and missiles on the densely inhabited strip.
Al Jazeera's Ayman Mohyeldin reporting from Gaza said there had been four air attacks in an hour as dusk fell on Wednesday.
One missile hit a mosque, one a field and another a vehicle moving near the border, he said. The fourth was said to have hit the home of a leading member of the Izz al-Din al-Qassam Brigades, Hamas’s military wing.
Early on Wednesday a Palestinian medic was killed when his ambulance was hit by an Israeli missile.
Four Israeli citizens have been killed in rocket and mortar attacks from the Gaza Strip since Israel began its offensive on Saturday.
Mark Regev, an Israeli government spokesman, said a "durable" solution was needed rather than the "band-aid" that would be provided by a 48-hour truce.
"What we need is a solution that will create real quiet ... the only people who really wanted this were Hamas, because we have been hitting them hard and they'd like time to regroup and rearm," he told Al Jazeera.
"To go through all this again a month from now will do no one any good, not the Palestinians in Gaza, not the Israelis living in the south facing the brunt of these incoming rockets.
Witnesses reported missiles hitting Hamas positions in Gaza City as well as the network of tunnels used for smuggling both basic supplies and weapons under the Gaza-Egypt border.
"Over the past 18 months those tunnels have really become a lifeline for the Palestinian people, but during these five days the tunnels have been destroyed," Mohyeldin said.
"Things are starting to run very low because not enough is coming through the crossings."
A senior United Nations official said it was crucial that the bombardment was halted so that fuel and food could be delivered.
"Conditions for parents and children in Gaza are dangerous and frightening. We are in a life or death situation for many people today," Maxwell Gaylard, UN humanitarian co-ordinator, said in a statement.
The Izz-al-Din al-Qassam Brigades said that it would step up rocket attacks against Israel if the bombardment was not ended.
"We tell the leaders of the enemy - if you continue with your assault, we will hit with our rockets further than the cities we have hit so far," a masked spokesman said in a televised statement.
Al Jazeera's Alan Fisher said that the Israel military was continuing to move men, tanks and armoured personnel carriers to the boundary with Gaza amid ongoing concerns that the aerial assault will be followed by a ground offensive.
"They are making it clear that if they wanted to have a ground assault they could do it and they certainly have the people in place to go ahead with that," he reported from southern Israel.
Mohyeldin said that in the event of a ground incursion, Palestinian factions felt that they had the advantage, due to the preparations they have made over the past six months of the truce.
"They say they have acquired new weapons, new munitions, new explosive devices and this is where they feel they enjoy more of an advantage in terms of the ability to face an Israeli incursion," he said.
"They certainly know they can't compete with Israel's air superiority and that is why Israel has been warned against launching a [ground] operation here in Gaza."
Bernard Kouchner, the French foreign minister, made two telephone calls to Ehud Barak, the Israeli defence minister, on Tuesday appealing to him to consider the 48-hour truce, two senior officials in Barak's office said.
|Israel has previously said it will not accept a truce unless rocket attacks stop [AFP]
The European Union added its voice to calls from the United Nations Security Council and the Middle East Quartet to end the violence.
"There must be an unconditional halt to rocket attacks by Hamas on Israel and an end to Israeli military action," an EU statement said.
"There is no military solution to the Israeli-Palestinian conflict, in Gaza or elsewhere."
Kouchner said on Wednesday that he and Nicolas Sarkozy, the French president, were considering visiting Israel next week in an effort to halt the fighting.
Other efforts to resolve the crisis were also taking place with Recep Tayyip Erdogan, the Turkish prime minister, visiting the region and Arab foreign ministers due to meet in Cairo.