WASHINGTON: US Secretary of State John Kerry traveled to Cairo early Monday for crisis talks on Gaza, following President Barack Obama's call for an “immediate ceasefire” between Israelis and Palestinians.

The US top diplomat is scheduled to meet with senior officials from Egypt and other countries, the State Department said, in a bid to halt a blistering land, sea and air assault that has sent thousands of terrified civilians fleeing their homes.

Kerry will seek “an immediate cessation of hostilities based on a return to the November 2012 ceasefire agreement,” the White House said, stressing the need to protect civilian life both “in Gaza and in Israel.

“According to the State Department, Kerry supports Egypt's initiative to bring about a ceasefire. His visit to the region comes in parallel with a high-profile peace mission by UN Secretary-General Ban Ki-moon.

Obama spoke Sunday by telephone with Israeli Prime Minister Benjamin Netanyahu to express his “serious concern” after more than 100 Palestinians and 13 Israeli soldiers were killed in the bloodiest day since the Gaza offensive was launched.

As more human remains are pulled from the rubble, the Palestinian death toll had risen to 501 by Monday, the fifth day of the Israeli ground operation.

Kerry's high-stakes trip came as US media reported that two American members of the Israeli Defense Force were killed in Gaza fighting.

The State Department said two US citizens were killed in Gaza violence, but did not immediately disclose their occupations.

Obama decries rising death toll

During their second call in three days, Obama and Netanyahu “discussed Israel's ongoing military operation,” including “the loss of Israeli soldiers, “the White House added.

Obama “raised serious concern about the growing number of casualties, including increasing Palestinian civilian deaths in Gaza and the loss of Israeli soldiers,” the White House said.

The US leader also condemned attacks by Hamas and “reaffirmed Israel's right to defend itself. “

“The president underscored that the United States will work closely with Israel and regional partners on implementing an immediate ceasefire, and stressed the need to protect civilians, in Gaza and in Israel.

“Kerry on Sunday did the rounds on the influential US television political talk shows, with Netanyahu also appearing on two of the TV programs.

Just before Kerry's 0515 GMT Monday departure from Andrews Air Force Base outside Washington, the UN Security Council deplored the mounting death toll in Gaza and appealed for an immediate ceasefire.

Meeting for two hours at an emergency session, the 15-member Council called for the respect of international humanitarian law, including the protection of civilians.

In a statement, the Council threw its support behind Egypt's bid to broker a truce as well as the peace mission by the UN's Ban, who is due in Kuwait on Monday before heading to Egypt, Israel and the Palestinian West Bank.

Egypt, which has been a mediator in previous Israel-Hamas conflicts, had proposed a halt to the fighting but Hamas rejected the initiative saying it had not been consulted. Israel initially accepted Cairo's plan.

Hamas has laid out a set of conditions, including the lifting of Israel's eight-year blockade on Gaza, the opening of the Rafah border crossing with Egypt and the release of scores of prisoners Israel re-arrested in recent weeks.

UN Security Council opens urgent talks on Gaza

The UN Security Council opened urgent talks on the escalating violence in Gaza to consider ways of stepping up ceasefire efforts.

The 15-member Council met as UN Secretary-General Ban Ki-moon was holding talks with leaders in the region amid a spike in violence that left more than 100 Palestinians dead in a single day in Shejaiya.

“We have to know from the secretary-general the result of his efforts, his travels and whether there is any hope of moving forward to a ceasefire,” said French Ambassador Gerard Araud as he headed into the meeting.

Israel’s TV channel retracts false allegations

Emergency services spokesman for the Gaza Strip Ashraf al-Qudra said 80 per cent of the Shejaiya fatalities were “old men, women and children.”

He said another 400 Palestinians were wounded there.

Palestinian president Mahmud Abbas had called for the urgent talks, saying the “situation is intolerable” in Gaza and describing the Israeli attacks as “crimes against humanity. “

Israel's UN envoy denies Israeli soldier abducted by Hamas

Israel's UN ambassador denied that an Israeli soldier had been abducted by Hamas. “Those rumors are untrue,” said Ambassador Ron Prosor when asked about the kidnapping.

Civilian casualties

“Children should be protected from the violence, and they should not be the victims of a conflict for which they have no responsibility,” Unicef's Catherine Weibel told AFP.

Israel's Prime Minister Benjamin Netanyahu absolved Israel of all responsibility Saturday for civilian casualties, laying the blame squarely on the shoulders of Hamas.

UNRWA has opened 49 of its schools to shelter those fleeing the most heavily-bombarded areas.

So far, more than 60,000 Gazans have sought sanctuary at UN institutions, the agency said.

As Ban headed for the region to help “end the violence and find a way forward”, Hamas said it had received an invitation to Cairo to discuss a ceasefire proposed by Egypt.

Earlier, Turkish Prime Minister Recep Tayyip Erdogan expressed his disappointment over Israel’s air campaign in the Gaza Strip, accusing the Jewish State of seeking a “systematic genocide” of the Palestinians.

“The Western world remains silent, so does the Islamic world. Because those who lost their lives are Palestinian, you can't hear their voices,” Erdogan said.

The outbreak of violence follows the kidnappings and killings of three Israeli teenagers in the West Bank, and the kidnapping and killing of a Palestinian teenager in an apparent revenge attack.

Thousands of pro-Palestinian demonstrators had turned out on the streets of London, Paris, Rome, New York, and other cities to call for an end to Israeli military strikes on Gaza.