NBC's Ayman Mohyeldin reports from Gaza City, where the streets remain empty as Palestinians brace themselves for overnight airstrikes as part of Israel's intense aerial campaign.
Updated at 11 p.m. ET: The day after Israeli aircraft bombed Hamas offices in Gaza and Hamas fired a rocket at Tel Aviv, Egypt's president said Saturday night that "some indications" exist that a ceasefire might be possible.
"There are some indications that there is a possibility of a ceasefire soon, but we do not yet have firm guarantees," Egyptian President Mohammed Morsi told a joint news conference with Turkish Prime Minister Tayyip Erdogan, who was visiting Cairo.
Egypt had brokered an informal truce in October that has since collapsed, and it has said it is working for a new deal.
Before dawn on Saturday, Israeli aircraft fired missiles at Gaza buildings that included the office of Gaza Prime Minister Ismail Haniyeh, as armed conflict in the region entered its fourth day.
Uriel Sinai / Getty Images
An Israeli missile from the "Iron Dome" defense system is fired Saturday to destroy a rocket fired from Gaza at Tel Aviv.
Hamas later retaliated, firing a rocket at Israel's biggest city, Tel Aviv, for the third straight day. Police said it was destroyed in mid-air by an Iron Dome anti-missile battery deployed hours earlier, and no one was injured.
But Hamas rocket fire appeared to be subsiding. The Israeli military said Sunday morning that Gaza militants hadn't attacked Israel since the night before.
Overnight, six journalists were wounded in Gaza City when Israeli warplanes hit a television station, according to Agence France-Presse. Reuters said witnesses identified the station as al Quds, which Israel sees as pro-Hamas. Sky News reported that around 5 a.m. local time, two missiles hit the building that houses its studios and offices. Al-Arabiya also said that its offices had been hit.
Medics say that 48 people living in Gaza were killed by early Sunday and more than 450 injured since Israel started airstrikes Wednesday, Agence France-Presse reported.
In the Israeli Mediterranean port of Ashdod, a rocket ripped into several balconies. Police said five people were hurt.
As the crisis escalates, Israel's military is considering waging a ground campaign. It started drafting 16,000 reserve troops on Friday, as Israel's Cabinet authorized the mobilization of up to 75,000 reservists. Troops were massing on the border and witnesses said they could see Israeli ships off Gaza's coast, NBC News' Ayman Mohyeldin reported.
In a broadcast statement, Hamas’s military wing, the Qassam Brigades, said a ground invasion would be "stupid and foolish."
The statement also said that Hamas has used sophisticated weapons – including locally made, long-range rockets -- to strike at Tel Aviv and Jerusalem.
Hamas says it blames Israel for the war, saying that Israeli leaders made “stupid” decisions that triggered the wrath of Hamas, and that has forced Israelis into bomb shelters.
NBC's Martin Fletcher and Richard Engle report from Tel Aviv and Gaza, where violence is ramping up.
Despite the violence, Tunisia's foreign minister arrived in the coastal enclave on Saturday in a show of solidarity, denouncing the Israeli attacks as illegitimate and unacceptable.
Officials in Gaza said 41 Palestinians, among them 20 civilians including eight children and a pregnant woman, had been killed in Gaza since Israel began operations four days ago. Three Israeli civilians were killed by a rocket on Thursday.
Israel's military said its air force had hit at least 180 targets since midnight, including a police headquarters, government buildings, rocket launching squads and a Hamas training facility in the impoverished territory.
NBC's Mike Viqueira and Martin Fletcher report on the latest developments in the ongoing crisis in the Middle East and each weigh in on what role the US would play in a possible ground offensive by Israel into Gaza.
Reporting from Gaza City, NBC's Richard Engel posted a message on Twitter describing the buzz of drones over the city. "It sounds like everyone is out mowing their lawns in the dark," he said.
A three-story house belonging to Hamas official Abu Hassan Salah was also hit and completely destroyed early on Saturday. Rescuers said at least 30 people were pulled from the rubble.
"What Israel is doing is not legitimate and is not acceptable at all," Tunisian Foreign Minister Rafik Abdesslem said as he visited Haniyeh's wrecked headquarters. "It does not have total immunity and is not above international law."
Hatem Moussa / AP
A ball of fire rises from an Israeli airstrike in Gaza City on Saturday.
Hamas says it is committed to continued confrontation with Israel and is eager not to seem any less resolute than smaller, more radical groups that have emerged in Gaza in recent years.
The Islamist Hamas has ruled Gaza since 2007. Israel pulled settlers out of Gaza in 2005 but has maintained a blockade of the territory.
Israel launched a massive air campaign on Wednesday with the declared aim of deterring Hamas from launching cross-border rocket salvoes that have plagued southern Israel for years.
The Palestinians have fired hundreds of rockets out of Gaza, including one at Jerusalem and three at Tel Aviv - Israel's commercial center. Jerusalem had not been targeted in such a way since 1970, and Tel Aviv since 1991.
Although there were no reports of casualties or damage in either city, the long-range attacks came as a shock and advanced the prospect of an Israeli ground invasion into Gaza.
NBC's Richard Engle reports from Gaza City, where residents are preparing for a potential invasion as Israeli drones fly overhead.
"This will last as long as is needed; we have not limited ourselves in means or in time," Foreign Minister Avigdor Lieberman told Israel's Channel One television on Saturday.
In a call with Israeli Prime Minister Benjamin Netanyahu on Friday, U.S. President Barack Obama reiterated American support for Israel to defend itself, Reuters reported. The two leaders also discussed options for "de-escalating" the situation, the White House said in a statement.
He also called Egypt's Morsi on Friday, and underscored his hope of restoring stability.
Netanyahu held a four-hour strategy session late on Friday with a clutch of senior ministers on widening the military campaign, while other cabinet members were polled by telephone on increasing mobilization.
Political sources said they decided to more than double the current reserve troop quota set for the Gaza offensive to 75,000. It did not necessarily mean all would be called up.
Suhaib Salem / Reuters
Palestinians inspect the destroyed office building of Hamas Prime Minister Ismail Haniyeh in Gaza City on Saturday.
In a further sign Netanyahu might be clearing the way for a ground operation, Israel's armed forces decreed a highway leading to the territory and two roads bordering the enclave of 1.7 million Palestinians off-limits to civilian traffic.
The Israeli military said some 367 rockets fired from Gaza had hit Israel since Wednesday and at least 222 more were intercepted by its Iron Dome anti-missile system.
The Israel Defense Force said Saturday that mortar fire from Gaza had damaged an electricity cable in the south of Israel. "As a result, power is out in areas of northern Gaza Strip," the IDF said in a message posted on Twitter.
Four Iron Domes were deployed initially and a fifth was rushed into action on Saturday, weeks ahead of schedule. The army said it was placed in the Tel Aviv area, showing Israel's concern for the safety of its heavily populated coastline.
Reuters contributed to this report.