It was "completely unacceptable" for Hamas, which controls Gaza, to launch attacks on Israel after a truce lasting several months, said Gordon Johndroe, a spokesman for the National Security Council.
"These people are nothing but thugs, so Israel is going to defend its people against terrorists like Hamas that indiscriminately kill their own people," Johndroe said in Texas as President George W. Bush spent the holidays at his ranch here. "They need to stop. We have said in the past that they have a choice to make. You can't have one foot in politics and one foot in terror."
Israeli Defense Minister Ehud Barak has warned that the operation in Gaza will widen as necessary. Asked if the United States would back a continuation of the retaliatory strikes, Johndroe said: "The U.S. doesn't want to see any more violence. I think what we've got to see is Hamas stop firing rockets into Israel. That's what precipitated this."
At the Bush ranch, Secretary of State Condoleezza Rice kept the president abreast of the situation. The president took a call from King Abdullah of Saudi Arabia, who wanted to discuss the violence that began eight days after a six-month truce between Israel and the militants expired.
"The United States strongly condemns the repeated rocket and mortar attacks against Israel and holds Hamas responsible for breaking the cease-fire and for the renewal of violence in Gaza," Rice said in a statement. "The cease-fire should be restored immediately. The United States calls on all concerned to address the urgent humanitarian needs of the innocent people of Gaza."
The Israeli army says Palestinian militants have fired some 300 rockets and mortars at Israeli targets over the past week. In recent days, Israeli leaders threatened to launch a major offensive.
Israeli warplanes launched counterattacks on dozens of security compounds across the Hamas-ruled territory in unprecedented waves of airstrikes. Most of those killed were security men, but an unknown number of civilians were also among the dead.
Hamas said all of its security installations were hit, threatened to resume suicide attacks, and sent at least 70 rockets and mortar shells crashing into Israeli border communities, according to the Israeli military. One Israeli was killed and at least six people were hurt.
With so many wounded, the Palestinian death toll was likely to rise. The strikes caused widespread panic and confusion in Gaza. Some of the Israeli missiles struck in densely populated areas as children were leaving school, and women rushed into the streets frantically looking for their children.
Johndroe said the U.S. was concerned that humanitarian needs were being met in Gaza. He urged Israel to avoid striking civilians, but he refrained from commenting specifically on positions that had been hit on the ground.
"I know they are targeting security and Hamas headquarters facilities," Johndroe said. "We urge them (the Israelis) to avoid civilian casualties."
"The message from the United States is that Hamas is a terrorist organization that is firing rockets into Israel and they fired them onto their own people as well," Johndroe said, noting reports he'd seen about the death of two Palestinian girls. "Hamas has done nothing for the people of Gaza."
The offensive has sparked angry protests throughout the Arab world. British Prime Minister Gordon Brown, the Vatican, the U.N. secretary-general and special Mideast envoy Tony Blair called for an immediate restoration of calm. The Arab League scheduled an emergency meeting Sunday to discuss the situation.