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Trump made the request during a meeting on Thursday with his top national security aides, including Vice President Mike Pence, his new Acting Defence Secretary Christopher Miller, and General Mark Milley, chairman of the Joint Chiefs of Staff, the official said on Monday.
The official confirmed the account of the meeting in The New York Times, which reported that the advisers persuaded Trump not to go ahead with a strike because of the risk of a broader conflict.
"He asked for options. They gave him the scenarios and he ultimately decided not to go forward," the official said.
The White House declined to comment.
Trump has spent all four years of his presidency engaging in an aggressive policy against Iran, withdrawing from the Iran nuclear deal negotiated by his Democratic predecessor, Barack Obama, and imposing economic sanctions against a wide variety of Iranian targets.
Trump, who is challenging the results of the November 3 presidential election, is to hand over power to Democratic President-elect Joe Biden on January 20.
His request for options came a day after a United Nations atomic watchdog report showed that Iran had finished moving a first cascade of advanced centrifuges from an above-ground plant at its main uranium enrichment site to an underground one, in a fresh breach of its nuclear deal with big powers.
Iran's 2.4 tonne stock of low-enriched uranium is now far above the deal's 202.8 kg limit. It produced 337.5 kg in the quarter, less than the more than 500kg recorded in the previous two quarters by the International Atomic Energy Agency.
In January, Trump ordered a US drone strike that killed Iranian military General Qassem Soleimani at the Baghdad airport.
But he has shied away from broader military conflicts and sought to withdraw U.S. troops from global hotspots in keeping with a promise to stop what he calls "endless wars."
A strike on Iran's main nuclear site at Natanz could flare into a regional conflict and pose a serious foreign policy challenge for Biden.