Rice said she was meeting not only with Israeli Prime Minister Ehud Olmert, but also with Palestinian Authority President Mahmoud Abbas as well as with allies at a gathering in Rome.
Asked why she didn't go earlier and engage in quick-hit diplomacy to try to end the fighting that has gripped the region, she replied, "I could have gotten on a plane and rushed over and started shuttling and it wouldn't have been clear what I was shuttling to do."
Daniel Ayalon, Israel's ambassador to Washington, told The Associated Press that Israel would not rule out an eventual international stabilization force in south Lebanon. But, he said, Israel was first determined to take out Hizbullah's command and control centers and weapons stockpiles.
He described it as a "mop-up" operation, and said that Israel had no desire to repeat its 18-year occupation of southern Lebanon that ended in 2000.
"They overplayed their hand, they miscalculated," Ayalon said of Hizbullah operatives based in southern Lebanon and supported by Syria and Iran.
"This is a war not of our choosing," he said. The flare-up in violence began after Hizbullah captured two Israeli soldiers and killed eight others in a cross-border operation last week.
Rice said the United States was committed to ending the bloodshed, but didn't want to do it before certain conditions were met. The United States has said all along that Hizbullah must first turn over the two Israeli soldiers who were captured and stop firing missiles into Israel.
"We do seek an end to the current violence, we seek it urgently. We also seek to address the root causes of that violence," she said. "A cease-fire would be a false promise if it simply returns us to the status quo."
Rice said that it was important to deal with the "root cause" of the violence, echoing what has been the US position since last week.
President George W. Bush, asked what he hopes Rice will achieve on her trip, said he would discuss it with her when he returns to the White House on Sunday. He was speaking at a restaurant in Aurora, Colo., as he met with 10 members of the military who recently returned from Iraq.
Announcing plans earlier for a weekend meeting that Bush and Rice will have with Saudi officials, White House spokeswoman Dana Perino said, "This is part of the president's broader diplomatic outreach on the developing situation in the Middle East."