The U.S. called Iran's recent aerial attack on Israel a "spectacular and embarrassing failure" saying that most of the missiles and drones fired by Tehran were intercepted.
"I've seen reporting that the Iranians meant to fail, that this spectacular and embarrassing failure was all by design," National Security Council spokesman John Kirby told a briefing on Monday.
"I've also seen Iran say that they provided early warning to help Israel prepare its defenses and limit any potential damage. All of this is categorically false," he added.
U.S. officials have previously said that Iran passed a message through Switzerland to Washington saying they intended to respond to a presumed Israeli strike in Syria that killed a top Iranian general.
But Kirby said claims that Tehran passed on the timing or targets of the attack in advance were "ridiculous."
The attack showed that Iran intended "clearly to cause significant destruction and casualties," he added.
U.S. President Joe Biden has proclaimed "ironclad" support for Israel's defense but the White House says it does not want any escalation of the situation or a wider Middle Eastern war.
Kirby said however it was an "Israeli decision to make" about whether and how it would respond.
Asked if Biden had urged Israel to show restraint after successfully seeing off Iran's attack, Kirby said the president "urged the prime minister to think about what that success says, by itself and to the rest of the region."
