The Obama administration considers Israel's blockade of Gaza to be untenable and plans to press for another approach to ensure Israel's security while allowing more supplies into the impoverished Palestinian area, senior American officials said Wednesday. The officials say that Israel's deadly attack on a flotilla trying to break the siege and the resulting international condemnation create a new opportunity to push for increased engagement with the Palestinian Authority and a less harsh policy toward Gaza. “There is no question that we need a new approach to Gaza,” said one official, who spoke on the condition of anonymity because the policy shift is still in the early stages. He was reflecting a broadly held view in the upper reaches of the administration. Israel would insist that any approach take into account three factors: Israel's security; the need to prevent any benefit to Hamas, the Islamist rulers of Gaza; and the four-year-old captivity of an Israeli soldier held by Hamas, Staff Sgt. Gilad Shalit. Since the botched raid that killed nine activists on Monday, the Israeli government has said that the blockade was necessary to protect Israel against the infiltration into Gaza of weapons and fighters sponsored by Iran. If there were no blockade in place, Prime Minister Benjamin Netanyahu said on Israeli television on Wednesday evening, it would mean “an Iranian port in Gaza.” He added, “Israel will continue to maintain its right to defend itself.” But the American officials said they believed that even Netanyahu understood that a new approach was needed. Yet Netanyahu has resisted American pressure in the past. The Obama administration initially demanded a complete freeze on Israeli settlements in the West Bank, but had to accept a 10-month partial freeze. Pressure on Israel also carries domestic political risks for Mr. Obama, given the passion of its supporters in the United States. The world powers have grown increasingly disillusioned with the blockade, saying that it has created far too much suffering in Gaza and serves as a symbol not only of Israel's treatment of Palestinians but of how the West is seen in relation to the Palestinians. “Gaza has become the symbol in the Arab world of the Israeli treatment of Palestinians, and we have to change that,” the senior American official said. “We need to remove the impulse for the flotillas. The Israelis also realize this is not sustainable.”