JERUSALEM—The Israeli security establishment is divided over whether it needs Washington's blessing if Israel decides to attack Iran, Israeli officials say, as the U.S. campaign for sanctions drags on and Tehran steadily develops greater nuclear capability.

Israeli children play on an army tank on display for celebrations in Jerusalem Tuesday for the 62nd anniversary of the founding of the state.

Some senior Israeli officials say in interviews that they see signs Washington may be willing to live with a nuclear-armed Iran, an eventuality that Israel says it won't accept. Compounding Israeli concerns were U.S. statements this past weekend that underscored U.S. resistance to a military option. Defense Secretary Robert Gates on Sunday discussed a memo to National Security Adviser James Jones warning that the U.S. needed new strategies, including how to contain a nuclear Iran—suggesting that Iran could reach nuclear capability without any foreign military force trying to stop it.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, reiterated Sunday the U.S. position that a military strike against Iran is a "last option."

Israel says it supports the U.S.-led push for new economic sanctions against Iran. But Israeli officials have increasingly voiced frustration over the slow pace of diplomatic efforts to get sanctions in place.

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