The U.N. Security Council will meet Thursday to discuss the mounting violence in the Gaza Strip, where 18 Palestinian civilians were killed in an Israeli attack early Wednesday.
The open meeting was announced after Qatar requested an emergency session.
Qatar is the only Arab member of the U.N. Security Council.
Officials in Europe and the Middle East have condemned the Israeli tank attack on the northern Gaza town of Beit Hanoun. U.N. officials voiced shock and dismay, and Secretary-General Kofi Annan called on Israel to end its military offensive in Gaza. He also urged the Palestinians to halt attacks against Israeli targets.
Israeli Prime Minister Ehud Olmert expressed regret for the deaths. The Israeli military says the attack was aimed at suspected rocket launching sites and vowed to continue its Gaza offensive.
Officials say the incident was the deadliest Israeli attack on Palestinians in four years. Palestinian Prime Minister and Hamas leader Ismail Haniyeh declared three days of mourning and vowed revenge.
In a statement, President Bush said the United States is deeply saddened by the injuries and loss of life in Gaza. He said he hopes Israel takes appropriate steps to avoid a repeat of the latest incident.
Israeli forces pulled out of Beit Hanoun Tuesday, after a week-long operation aimed at ending rocket attacks on Israel. Hours after Israeli troops withdrew, Palestinian militants fired a barrage of rockets at the Israeli city of Ashkelon.