JERUSALEM — An Israeli newspaper reported Sunday that the Obama administration’s top security official has briefed Israel on U.S. plans for a possible attack on Iran, seeking to reassure it that Washington is prepared to act militarily should diplomacy and sanctions fail to pressure Tehran to abandon its nuclear enrichment program.

A senior Israeli official, speaking on condition of anonymity to discuss confidential talks, said the article in the Haaretz daily was incorrect.

Haaretz said National Security Adviser Tom Donilon laid out the plans before Israeli Prime Minister Benjamin Netanyahu during a dinner at a visit to Israel earlier this month. It cited an unidentified senior American official as the source of its report, which came out as presumptive Republican presidential nominee Mitt Romney was telling Israel he would back an Israeli military strike against Iran.

The American official also said Donilon shared information on U.S. weapons that could be used for such an attack, and on the U.S. military’s ability to reach Iranian nuclear facilities buried deep underground, the newspaper said. It cited another U.S. official involved in the talks with Israel as concluding that “the time for a military operation against Iran has not yet come.”

The Israeli official, speaking on condition of anonymity to discuss a confidential meeting, said, “Nothing in the article is correct. Donilon did not meet the prime minister for dinner, he did not meet him one-on-one, nor did he present operational plans to attack Iran.” He had no information when asked if Donilon had discussed any kind of attack plans with any Israeli official. Haaretz said another Israeli official attended for part of the meeting.

The U.S. Embassy had no immediate comment. Haaretz cited Tommy Vietor, a spokesman for the U.S. National Security Council, as declining to comment on the confidential discussion between Netanyahu and Donilon.

Both Israel and the U.S. think Iran’s ultimate aim is to develop weapons technology, and not just produce energy and medical isotopes as Tehran claims. U.S. officials are concerned Israel might attack Iranian nuclear facilities prematurely, and have been trying to convince Israeli leaders they can depend on Washington to keep Iran from becoming a nuclear power.

Israeli leaders have repeatedly said they would not contract out their country’s security to another nation.

In Jerusalem on Sunday, a top Romney foreign policy adviser told reporters, “If Israel has to take action on its own, in order to stop Iran from developing the capability (to build a nuclear weapon), the governor would respect that decision.” Romney also thinks the option of a U.S. attack should also be on the table.