Clinton is scheduled to arrive in Jerusalem later tonight to meet with Israel Prime Minister Benjamin Netanyahu, according to Deputy National Security Advisor Ben Rhodes. Clinton will also meet with Palestinian officials in Ramallah before heading to Cairo to meet with leaders in Egypt.
A senior Israeli government official told ABC News that Netanyahu has decided to hold off on a ground invasion for a "limited time" in favor of a diplomatic solution.
Overnight, Israeli jets hit more than 100 targets, killing five people. Gaza militants blasted more than 60 rockets in retaliation, with one of them hitting a bus in southern Israel.
Click HERE for Photos from Airstrikes and Rocket Attacks in the Middle East
An Israeli man armed with an axe and knife stabbed a guard at the U.S. Embassy in Tel Aviv. The guard was wounded in the attack, but expected to live. Police apprehended the man at the scene, police said.
The man, in his early 40s, attacked the guard outside the embassy gates, police spokesman Micky Rosenfeld told The Associated Press. He said the man's motive was unknown, but political motives were not suspected and the incident had nothing to do with Israel's battle with Hamas militants in the Gaza Strip.
"It's in nobody's interest to see this escalate," Rhodes said at a press conference in Phnom Penh, Cambodia, where President Obama is attending the East Asia Summit.
Clinton, who was with Obama on his trip to Southeast Asia, hastily departed from Cambodia for the Middle East following the announcement.
A State Department official tells ABC News that Clinton's visit "will build on American engagement with regional leaders over the past days."
A White House official said they believe face-to-face diplomacy could help, but no concrete details were offered.
President Obama was on the phone until 2:30 a.m. local time with leaders in the region trying to de-escalate the violence, Rhodes told reporters. The president spoke with Netanyahu and Egyptian President Morsi on Monday as well.
"To date, we're encouraged by the cooperation and the consultation we've had with the Egyptian leadership. We want to see that, again, support a process that can de-escalate the situation," Rhodes said. "But again, the bottom line still remains that Hamas has to stop this rocket fire."
Rhodes insisted that Palestinian officials need to be a part of the discussions to end the violence and rocket fire coming out of the Hamas-ruled territory.
"The Palestinian Authority, as the elected leaders of the Palestinian people, need to be a part of this discussion," Rhodes said. "And they're clearly going to play a role in the future of the Palestinian people?a leading role."
With the death toll rising, Egypt accelerated efforts to broker a cease-fire Monday. Anger boiled over in Gaza as the death toll passed 100 and the civilian casualties mounted. Volleys of Palestinian militant rockets flew into Israel as Israeli drones buzzed endlessly overhead and warplanes streaked through the air to unleash missile strikes.
An Israeli strike on a Gaza City high-rise Monday killed Ramez Harb, one of the top militant leaders of Islamic Jihad, the Palestinian militant group said.
It is also the second high profile commander taken out in the Israeli offensive, which began seven days ago with a missile strike that killed Ahmed Jibari, Hamas' top military commander.
ABC News' Reena Ninan, Dana Hughes, Mary Bruce and Matt Gutman contributed to this report.