Obama urges 'immediate ceasefire,' sends Kerry for talks

President Barack Obama called for an "immediate ceasefire" in Gaza on Sunday, on the bloodiest day of fighting between Israelis and Palestinians, and dispatched top US diplomat John Kerry for talks with regional leaders.

Obama spoke by telephone with Prime Minister Benjamin Netanyahu to express his concern after more than 100 Palestinians and 13 Israeli soldiers were killed in one day.

Obama, who also condemned attacks by Hamas on Israel, "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 in a statement.

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

It said Obama "reaffirmed Israel's right to defend itself."

The two leaders spoke after Kerry did the rounds on US television talk shows, with Netanyahu also appearing on two of the programs.

Kerry will travel to Cairo on Monday, where he will meet with senior officials from Egypt and other countries about the struggle in Gaza, the State Department said.

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

According to the State Department, Kerry is standing behind Egypt's initiative to back those efforts.