The Israeli military has continued its offensive in Gaza, targeting a major mosque and a university, as diplomatic solution appears more remote after Israel announced that it would not attend the talks set in Cairo.

Bombardments continue across the Palestinian territory including the southern district of Rafah on Saturday afternoon, Al Jazeera's Imtiaz Tyab, reporting from Gaza, said.

There are some signs of Israeli tanks pulling out of some areas and back to the border, with Israeli government indicating that it was close to destroying Hamas cross-border tunnels.

However, Prime Minister Benjamin Netanyahu, speaking in Tel Aviv on Saturday, vowed that the operation will continue saying, "It does not matter how time we need. We will achieve our goal."

A photo of the Islamic University of Gaza taken just a month before the Israeli assault [university website]

As of late Saturday, Gaza health ministry officials reported that the death toll has now risen 1,677 Palestinians, and our correspondent said that the number could rise further.

"We have seen a lot of fighting there with over 120 people killed in a 24-hour period, and we have on good authority that that number is much higher, but the reason it has not been updated is that nobody could get into Rafah," he said.

Among those who were killed 378 are children, 86 are women and 58 are elderly men. There were also 63 Israeli soldiers killed as well as three civilians in the Israeli side.

As news of mounting Palestinian casualties comes, an Israeli official told the AFP news agency that Prime Minister Benjamin Netanyahu will not send his representatiatives to the truce negotiations in Egypt.

"Hamas is not interested in an accommodation," the official said, accusing the group of misleading international mediators.

A Palestinian delegation including Hamas officials was due to arrive later on Saturday in Cairo for the talks, although Al Jazeera's Dalia Hatuqa, who is reporting from the West Bank, said that at least three representatives of Hamas and the Islamic Jihad group have been barred from entering Egypt through the Rafah crossing.

'No red lines'

On Saturday, Israeli aircraft struck a large part of the Islamic University in Gaza City and the Imam Shafi mosque, which can accommodate as many as 3,000 people.

At the Islamic University, glass from broken windows and notebooks belonging to some of the thousands of students were scattered around the premises. No casualties were reported in the strike.

"The university is now in complete ruins," Al Jazeera’s Imtiaz Tyab, reporting from the scene just two hours after the bombardment, said.

The Israeli army said it targeted a "weapon development" centre in the university.

In a twitter post, the military said it struck 200 "terror targets" in 24 hours.

One of Gaza City's largest mosques, Shifa mosque, was also badly damaged by an Israeli strike.

"Over the past several days, it's becoming very clear that there are no red lines," he said. "At least six hospitals have been targeted, and we know that UN schools where people were sheltering, have been targeted."

Israeli forces on Saturday sealed off the eastern Rafah area, and warned that cars on the streets would be considered potential targets, Al Jazeera’s Charles Stratford, reporting from southern Gaza, said.

Further north, Israeli military said they are winding down operation and told residents of Beit Lahiya that they could now return to their homes.

Al Jazeera's Nicole Johnston reported seeing tanks pulling out, but added that "it is difficult" to determine scale of the withdrawal. But she added that so far many residents have refused to follow the advise out of fear for their lives.

"People are saying to us, at this stage they are not returning home. They don't trust Israel. No one feels safe enough to return home at this stage," she said, adding that shelling can still be heard on late on Saturday.

In Cairo, Egyptian President Abdel Fattah El-Sisi said the truce plan Egypt proposed last month provided a "real chance" to end the Gaza conflict, stressing the need for its speedy implementation.

"Time is decisive, we have to take advantage of it quickly to douse the fire in the [Gaza] Strip... and to stop the bloodshed of Palestinians," he said.