Updated: 5:10 p.m. ET
GAZA CITY, Gaza Strip Israeli aircraft struck crowded areas in the Gaza Strip and killed a senior militant with a missile strike on a media center Monday, driving up the Palestinian death toll to 96, as Israel broadened its targets in the 6-day-old offensive meant to quell Hamas rocket fire on Israel.
The Israeli military insists its strikes target only militants -- with surgical precision -- and they say they're hitting those targets. CBS News correspondent Charlie D'Agata reports that in one of the most densely populated places on the planet, civilian casualties are inevitably mounting.
Escalating its bombing campaign over the weekend, Israel began attacking homes of activists in Hamas, the Islamic militant group that rules Gaza. These attacks have led to a sharp spike in civilian casualties, killing 24 civilians in just under two days and doubling the number of civilians killed in the conflict, a Gaza health official said.
D'Agata saw what was left Monday morning of a police headquarters that was completely destroyed by two bombs overnight. It was a legitimate target; considered part of the Hamas security apparatus, and it was a surgical strike, but the Israeli missiles blew out all the windows of homes nearby. There's a reason the Isreali military attacks at night. With such a ferocious explosion, anybody on the street would likely have been killed.
Israeli military sources said the IDF caused severe damage to dozens of targets Monday, including underground rocket launchers, a training facility, a police station and an ammunition storage facility. They said Israel also targeted and hit a vehicle used for carrying weapons as well as 50 smuggling tunnels.
Hamas fighters have fired hundreds of rockets into Israel in the current round of fighting, including 75 on Monday, among them one that hit an empty school. Schools in southern Israel have been closed since the start of the offensive Wednesday. Twenty rockets were intercepted by the Iron Dome anti-missile battery, police spokesman Micky Rosenfeld said. Rockets landed in open areas of Beersheva, Ashdod, Asheklon.
The rising toll came as Egyptian-led efforts to mediate a cease-fire between Israel and Hamas got into gear.
Egypt's President Mohammed Morsi has said repeatedly that he's hopeful a ceasefire agreement can be reached quickly, but a source close to the Hamas delegation in Cairo told CBS News correspondent Clarissa Ward on Monday morning that, thus far, the talks had hit a brick wall.
Ward says part of the reason for the impasse may be that Hamas is making some big demands in exchange for stopping its rocket attacks on Israel -- it wants an end to Israel's five year blockade of the Gaza Strip, which Israel is unlikely to budge on due to fears that it would lead to an influx of weapons to militants inside Gaza.
While Israel and Hamas were far apart in their demands, both sides said they were open to a diplomatic solution -- and prepared for further escalation if that failed.
The leader of Hamas took a tough stance, rejecting Israel's demands that the militant group stop its rocket fire. Instead, Khaled Mashaal said, Israel must meet Hamas' demands for a lifting of the blockade of Gaza.
"We don't accept Israeli conditions because it is the aggressor," he told reporters in Egypt. "We want a cease-fire along with meeting our demands."
An Israeli official said Israel hoped to find a diplomatic solution to the crisis as well and signaled Egypt was likely to play a key role in enforcing any truce.
"We prefer the diplomatic solution if it's possible. If we see it's not going to bear fruit, we can escalate," he said, speaking on condition of anonymity because of the sensitive diplomatic efforts underway.
The official said Israel doesn't want a "quick fix" that will result in renewed fighting months down the road. Instead, Israel wants "international guarantees" that Hamas will not rearm or use Egypt's neighboring Sinai peninsula for militant activity.
A poll published in the Haaretz daily on Monday showed widespread support in Israel for the offensive. It said that 84 percent of the public supports the operation, with 12 percent opposed. At the same time, it said just 30 percent of the public supports a ground invasion of Gaza. The poll, conducted by the Dialog agency, surveyed 520 people and had a margin of error of 4.4 percentage points.
Overall, the offensive that began Wednesday killed 96 Palestinians, including 50 civilians, and wounded some 720 people, Gaza heath official Ashraf al-Kidra said. Among the wounded were 225 children, he said.
On the Israeli side, three civilians have died from Palestinian rocket fire and dozens have been wounded. The rocket-defense system has intercepted hundreds of rockets bound for populated areas.
In Monday's violence, an Israeli air strike on a high-rise building in Gaza City killed Ramez Harb, a senior figure in Islamic Jihad's military wing, the Al Quds Brigades, the group said in a text message to reporters. A number of foreign and local news organizations have offices in the building, which was also struck on Sunday. A passer-by was also killed, medics said.
Thick black smoke rose from the building. Paramedics said several people were wounded.
Islamic Jihad, a smaller sister group to Hamas, said it believed Harb was the target of the strike.
Israel has killed dozens of wanted militants in surgical strikes throughout the operation, the result, officials say, of intelligence gathered from its collection of high-flying drones overhead and a network of informants.
Before dawn Monday, a missile struck a three-story home in the Gaza City's Zeitoun area, flattening the building and badly damaging several nearby homes. Shell-shocked residents searching for belongings climbed over debris of twisted metal and cement blocks in the street.
Egypt is trying to broker a cease-fire with the help of Turkey and Qatar. Turkish Foreign Minister Ahmet Davutoglu and a delegation of Arab foreign ministers were expected in Gaza on Tuesday.
A senior Egyptian official told The Associated Press that Hamas and Israel were each presenting Egypt with their conditions for a cease-fire.
"I hope that by the end of the day we will receive a final signal of what can be achieved," said the official, who is familiar with the indirect negotiations. He said Israel and Hamas are both looking for guarantees to ensure a long-term stop to hostilities. The official says Egypt's aim is to stop the fighting and "find a direct way to lift the siege of Gaza."
The official spoke on condition of anonymity because of the sensitivity of the indirect negotiations.
The rising toll was likely to intensify pressure on Israel to end the fighting. Hundreds of civilian casualties in an Israeli offensive in Gaza four years ago led to fierce international condemnation of Israel.
But Mashaal said Gazans were prepared to keep fighting.
"Gaza's demand is not a halt to war. Its demand is for its legitimate rights," including a stop to Israeli attacks, assassinations and a lifting of the blockade, Mashaal said.