President Bush strongly defended Israel's attacks in Lebanon on Thursday but worried they could weaken or topple the fragile government in Beirut. The Mideast violence exposed divisions between the United States and allies and raised fears of a widening war.

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"Israel has a right to defend herself," Bush said at a joint news conference with German Chancellor Angela Merkel. "Every nation must defend herself against terrorist attacks and the killing of innocent life."

Merkel appealed for restraint by all sides and said it was up to the militant group Hezbollah to defuse the situation, triggered by its cross-border raid from Lebanon into Israel and the capture of two Israeli soldiers. She called the violence a "very disturbing situation" that "fills us with concern."

The Mideast eruption came at an awkward time for Bush. His strong support of Israel put him sharply at odds with European Union allies two days before a summit of world leaders in Russia, where the United States is counting on a united stand against Iran's nuclear ambitions and North Korea's long-range missile test. The violence also presents Bush with yet another major crisis in the Middle East, along with the Iraq war and the Iran standoff.

Secretary of State Condoleezza Rice said Syria must act responsibly and bring pressure on those involved.

"This is a situation that can be resolved if parties take responsible action," Rice said at a news conference later in the day.