The U.N. Security Council says it is deeply concerned about the loss of civilian life in southern Israel and Gaza.
The Council adjourned its emergency session early Sunday and issued a statement that condemns the escalation of violence and calls for all parties to respect their obligations under international law.
In a briefing to the council late Saturday, U.N. Secretary-General Ban Ki-moon said he recognized Israel's right to defend itself but condemned what he called "the disproportionate and excessive used of force."
He also condemned Palestinian rocket attacks on Israel and called for the immediate cessation of such acts of terrorism.
Violence continued in northern Gaza early Sunday, as Israeli warplanes destroyed the offices of the Hamas leader in Gaza, Ismail Haniyeh.
Palestinian medical workers say dozens of civilians, including women and children, are among the dead.
President Bush's national-security spokesman, Gordon Johndroe, said the United States regrets the loss of life on both sides, but he also noted, "There is a clear distinction between terrorist rocket attacks that target civilians and action in self defense."
Israeli Defense Minister Ehud Barak says the Jewish state also regrets the civilian casualties. Israel says rockets fired from Gaza into Israeli population centers triggered the clashes, and that Hamas bears full responsibility for the extent of the violence.
Palestinian officials say the Israeli incursion could destroy the peace process. U.S. Secretary of State Condoleezza Rice is leaving for the Middle East Monday. Expanded meetings with both Israeli and Palestinian officials are on her agenda.
Since Wednesday, when a cross-border rocket attack killed an Israeli civilian, Israel's attacks have killed at least 80 Palestinians in Gaza.
Some information for this report provided by AP, AFP and Reuters.