The United States received advance notice of Israel's reported strike on Iran but did not endorse the operation or play any part in its execution, US media quoted officials as saying. NBC and CNN, citing sources familiar with the matter and a US official, respectively, said Israel had provided Washington with pre-notification of the strike.
Various networks cited officials confirming a strike had taken place inside Iran, with CNN quoting one official as stating the target was not a nuclear facility.
Israel told the United States on Thursday it would be retaliating against Iran in the coming days, a senior US official told CNN.
"We didn't endorse the response," the official said, according to CNN.
There was no immediate comment from the White House about the Israeli strike.
In response to a query from AFP, the Pentagon duty desk said: "We do not have anything to offer at this time."
Iran activated its air defense system over several cities, state media reported, after the country's official broadcaster said explosions were heard near the central city of Isfahan.
Israel warned it would hit back after Iran fired hundreds of missiles and drones at its arch-foe over the weekend. Most of them were intercepted.
That weekend barrage came in the wake of an attack on Iran's consulate in Damascus widely blamed on Israel.
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