President Bush said Tuesday he suspects Syria is trying to reassert influence in Lebanon more than a year after Damascus ended what had effectively been a long-term military occupation of its smaller, weaker neighbor.

"It's in our interest that Syria stay out of Lebanon and this government survive," Bush said in a reference to the young, Lebanese government.

Bush spoke at the White House after briefing members of Congress about his recent trip to Russia for an economic summit that was overshadowed by fighting between Israel and the Islamic militant group Hezbollah.

"Everybody abhors the loss of innocent life," Bush said. "On the other hand, what we recognize is that the root cause of the problem is Hezbollah. And that problem must be addressed ... by making it clear to Syria that they've got to stop their support to Hezbollah."

He said there are suspicions that instability caused by Hezbollah's attacks will cause some in Lebanon to invite Syria to return to the nation.

"Listen, Syria is trying to get back into Lebanon, it looks like to me," said Bush, who also noted the backing Hezbollah receives from Iran.

"In order to be able to deal with this crisis, the world must deal with Hezbollah, with Syria and to continue to work to isolate Iran," Bush said.

The president reiterated his stance that Israel should be free to respond to attacks, but warned against triggering the collapse of the Lebanese government run by Prime Minister Fuad Saniora.

"We have made it very clear that Israel should be allowed to defend herself," Bush said. "We've asked that as she does so that she be mindful of the Siniora government. It's very important that this government in Lebanon succeed and survive."

Fighting began June 25 when Hamas-linked militants in the Gaza Strip carried out a cross-border attack on a military outpost in Israel, killing two soldiers and capturing one. Hezbollah guerrillas joined the fray in July, attacking a military patrol on the border in northern Israel, killing three soldiers and capturing two. Both Hamas and Hezbollah have said the attacks were not related.

Secretary of State Condoleezza Rice, who spoke Monday with Israeli Prime Minister Ehud Olmert, said Tuesday that any cease-fire in Mideast fighting ought to be based on fundamental changes that could lead to a lasting impact.

"We all want a cessation of violence," Rice said. "We all want the protection of civilians. We have to make certain that anything that we do is going to be of lasting value."

Rice said there must be a conducive environment for a cease-fire. That, she said, would involve implementation of a standing U.N. Security Council resolution and the deployment of the Lebanese army to the borders, as well as the introduction of a strong peacekeeping operation.

A U.N. Security Council resolution in 2004 led to withdrawal of Syrian forces from Lebanon. But its call for disarming militant guerrillas has not been heeded.

Rice, at a joint news conference with Egyptian Foreign Minister Ahmed Aboul Gheit, also indicated she would not be going to the troubled region immediately. She said she was primed to take the trip when it will be "helpful and necessary."

Rice's skepticism about trying to work out an immediate, makeshift cease-fire reflects views shared by the Israeli government in seeking fundamental changes to guard against another flare-up. These include ensuring southern Lebanon does not remain a launching pad for attacks on Israel.

Gheit, for his part, did not qualify his support for a cease-fire. He said one was under discussion in diplomatic circles.

Speaking to reporters after the lawmakers' meeting with the president, Sen. Joseph Biden, D-Del., said he agreed with Bush that the United States should respond to the crisis by pressuring Hezbollah, Syria and Iran.

"I think the president has an opportunity here to turn — as an old phrase goes — lemons into lemonade," Biden said, adding that some of Lebanon's Arab neighbors are publicly siding with the United States and Europe against Hezbollah.

"I think he's started down that road, and I think he has a shot," Biden said.