The US tonight vetoed an Arab-backed United Nations Security Council resolution that would have demanded that Israel halt its military offensive in the Gaza Strip.
The draft, sponsored by Qatar, accused Israel of a "disproportionate use of force" that endangered Palestinian civilians, and demanded Israel withdraw its troops from Gaza.
Earlier UN Secretary-General Kofi Annan announced he was sending a three-person team to the Middle East to urge all parties to exercise restraint.
The team will first visit Cairo to meet with Egyptian officials and consult with Arab League foreign ministers meeting there on Saturday, a spokesman said.
The team is then expected to head to Israel, the Palestinian territories, Lebanon, Syria and possibly other destinations "as needed," the spokesman added.
Vijay Nambiar, Mr Annan's political adviser, is to head the team. The other members are UN Middle East envoys Terje Roed Larsen and Alvaro de Soto.
The team would also urge all sides to respect international humanitarian law on the need to protect civilians and civilian institutions in military settings, the UN said.
President Bush has defended Israel's attacks on targets in Lebanon but said the Israelis should be careful not to weaken the fragile government there.
Mr Bush and German Chancellor Angela Merkel, at a joint news conference after talks in northeastern Germany, made clear they felt Israel's actions in seeking kidnapped soldiers and responding to Hizbullah rocket attacks were justified.
"Israel has the right to defend herself," Mr Bush said. "Secondly, whatever Israel does though should not weaken the Siniora government in Lebanon," he added, referring to Lebanese Prime Minister Fouad Siniora.