PHNOM PENH, Cambodia » President Barack Obama dispatched Secretary of State Hillary Rodham Clinton to the Middle East today as the U.S. urgently seeks to end a conflict between Israel and Hamas that has killed more than 100 in the last week.

Clinton hastily departed for the region from Cambodia, where she had joined Obama for a summit with Asian leaders. The White House said she would make three stops, meeting with Israeli Prime Minister Benjamin Netanyahu in Jerusalem, Palestinian officials in Ramallah, in the West Bank, and Egyptian leaders in Cairo. Clinton was expected to arrive in Israel tonight and return to Washington late Wednesday or very early Thursday after making all three stops.

Clinton’s trip marks the Obama administration’s most forceful engagement in the conflict that has killed more than 100 Palestinians and three Israelis, with hundreds more wounded. While the U.S. has backed Israel’s right to defend itself against rocket fire from Gaza, Washington has warned its ally against pursuing a ground assault that would further escalate the violence and could dramatically increase casualties on both sides.

Ahead of Clinton’s arrival, Obama spoke by telephone for almost a half-hour with Egyptian President Mohammed Morsi, commending the Islamist leader’s efforts to de-escalate tensions, said Ben Rhodes, deputy national security adviser. It was their third conversation in 24 hours.

Obama wants a diplomatic solution urgently because "there would be significant loss of life associated with further conflict," Rhodes told journalists traveling with the president from Cambodia to Japan.

In Washington, two diplomats familiar with confidential deliberations said Israel was considering a possible cease-fire but might hold off on a formal announcement until after Clinton’s arrival. They added, however, that Israel would stop its operations even without a formal truce, if rocket fire from Gaza ceased. The diplomats spoke on condition of anonymity because they weren’t authorized to speak publicly on the discussions.

Israel and Hamas both have said they’re open to diplomatic mediation efforts being led by Egypt. Hamas officials signaled today that a deal was close.

Clinton isn’t heading to the Middle East with any specific proposal to broker a peace deal, U.S. officials said. She’ll reassure Israel it has full American support while urging it to limit civilian casualties, and she will press members of the Western-backed Palestinian government in the West Bank to influence its brethren in Gaza to halt the rocket fire.

In Cairo, Clinton will strike a similar note by reminding the Egyptian government of its peace obligations with Israel under a treaty they share, said officials who spoke on condition of anonymity because they weren’t authorized to talk publicly about the matter.

Rhodes said the U.S. and Israel want to see the conflict ended "diplomatically and peacefully." But he said Washington understands the Jewish state’s need for a "durable outcome that ends the rocket attacks on Israeli cities and restores a broader calm in the region" — a reference to Israel’s concerns that its cease-fires with Hamas have become ever shorter in duration and increasingly tenuous.

Obama and Clinton have consulted about the widening crisis throughout their three-day tour of Southeast Asia, their final joint trip before Clinton leaves her post as the top U.S. diplomat. They spoke again about the situation this morning, aides said, and made the decision for her to travel to the region. Still, it was unclear what impact Clinton’s presence would have on the violence.

"There are a number of ideas that are in play," Rhodes said, but offered no further details. He insisted the ramped up U.S. involvement was "a matter of what’s in everybody’s best interests", not a matter of "leverage."

Obama and Clinton each have held multiple telephone calls with their counterparts in Israel and Egypt, which is at the center of negotiations to quell the violence. Because the U.S. considers Hamas a terrorist organization and prohibits contact between its members and American officials, it is relying on Egypt, as well as Turkey and Qatar, to deliver its message to the Hamas leadership in Gaza.

Hamas wants Israel to halt all attacks on Gaza and lift tight restrictions on trade and movement in and out of the territory that have been in place since Hamas seized Gaza by force in 2007. Israel demands an end to rocket fire from Gaza and a halt to weapons smuggling into Gaza through tunnels under the border with Egypt.

The widening conflict distracted from Obama’s three-country tour of Southeast Asia, his first overseas trip after winning re-election. The president, after a marathon day that took him from Thailand to Myanmar to Cambodia, worked the phones with Mideast leaders into the early hours of this morning, aides said. He departed Cambodia later today, and was expected to arrive in Washington before dawn Wednesday.

Associated Press writer Matthew Lee and Bradley Klapper in Washington contributed to this report.