President Barack Obama insisted on Sunday that Israel had a right to defend itself but said it would be "preferable" to avoid an Israeli ground offensive in Gaza.
He said persuading Israel not to attack would depend on the success of efforts by Middle East leaders to bring a halt to Hamas rocket fire into Israel.
"There's no country on earth that would tolerate missiles raining down on its citizens from outside its borders," Obama told a news conference during a visit to Thailand. "We are fully supportive of Israel's right to defend itself."
Israeli forces struck Gaza for a fifth straight day on Sunday and its military prepared for a possible ground invasion, although Egypt, which is trying to mediate, held out hopes that a ceasefire could be reached.
Asked whether he believed an Israeli ground invasion would be an escalation of the conflict and if he would support such a move anyway, Obama said he had been in regular contact with Egyptian and Turkish leaders to secure their help in stopping Hamas's rocket barrages, which he called the "precipitating event" in the conflict.
"My message to all of them was Israel has every right to expect that it does not have missiles fired into its territory," Obama said in his first public comments on the Gaza crisis.
"If this can be accomplished without a ramping up of military activity in Gaza, that is preferable, that's not just preferable for the people of Gaza, it's also preferable for Israelis because if Israeli troops are in Gaza they're much more at risk of incurring fatalities or being wounded," he said.
"We're going to have to see what kind of progress we can make in the next 24, 36, 48 hours," Obama added.
Meanwhile, Foreign Minister Avigdor Liberman said Sunday that the government is open to discussing with its foreign partners ways to de-escalate the conflict but not while terror groups in Gaza continue to fire rockets at Israel.
"We are willing to consider all the suggestions offered by our friends in the world," Liberman said, "but the first and most important condition is that terror organizations in Gaza must stop firing.
"As soon as they commit to stop firing, we are prepared to consider all proposals raised."
In this respect, the Egyptian foreign ministry announced Sunday that UN Secretary-General Ban Ki-moon is set arrive in Egypt on Monday for talks with the Egyptian president and other officials. Egypt is negotiating a truce over Gaza and President Mohamed Morsi, who Ban is due to meet on Tuesday, has said there were "some indications" that a deal could be soon.
In the interim, Arab League chief Nabil Elaraby told reporters in Cairo Sunday that a delegation of Arab foreign ministers will visit Gaza on Tuesday to show solidarity with Palestinians. A League source said Elaraby would lead the delegation.