U.S. Navy Boeing F/A-18 E and F Super Hornet strike fighters from the USS Abraham Lincoln (CVN-72) were poised to bomb Iranian surface-to-air missile (SAM) sites and radars Thursday evening when they were abruptly recalled and their mission aborted.

While the exact reasons for aborting this strike mission against Iran is unclear at the moment, The New York Times reports president Donald Trump got cold feet at the last minute and countermanded the attack order he'd given a few hours before.

The Times said it isn't clear if Trump had changed his mind about attacking Iran, or if the administration changed course due to a change in strategy. It said future attacks on Iran haven't been ruled out.

Trump is said to have approved military strikes on several Iranian targets in retaliation for Iran shooting down a Navy Northrop Grumman BAMS-D over the Strait of Hormuz. BAMS-D is a prototype, or early version, of the RQ-4A unmanned maritime surveillance and patrol aerial drone.

Why manned strike fighters instead of cruise missiles were selected for the attack also hasn't been made clear. No cruise missiles were fired on an Iranian target.

The Times said Trump had earlier approved the attacks and White House officials were still expecting the attack to go ahead as late as 7:00 p.m. ET on Thursday.

Warships of Carrier Strike Group Twelve (CSG-12), led by its flagship, the USS Abraham Lincoln, were poised to attack Iranian SAM and radar sites when they received the order to stand down. CSG-12 also includes Carrier Air Wing Seven; the Ticonderoga-class cruiser USS Leyte Gulf (CG-55), and the Arleigh Burke-class guided-missile destroyers, USS Mitscher (DDG-57), USS Gonzalez (DDG-66), USS Winston S. Churchill (DDG-81), USS Mason (DDG-87) and USS Nitze (DDG-94).

The "teeth" of Carrier Air Wing Seven consists of four squadrons of F-18 E/F Super Hornets.

On Thursday morning, Trump tweeted "Iran made a very big mistake!" by shooting down the U.S. spy drone.  Trump later said during a TV interview that "I think they made a mistake, and I'm not just talking the country made a mistake. I think that someone under the command of that country made a big mistake."

The United States was widely expected to retaliate to Iran shooting down the spy drone. Navy officials cited by U.S. media said the drone was shot down by an Iranian surface-to-air missile in international airspace over the Strait of Hormuz. The Iran Revolutionary Guard Corps (IRGC), however, disputed this claim, saying the $180 million drones was blasted out of the sky over Iran's southern coastal province of Hormozgan.

"The US-made Global Hawk surveillance drone was brought down" in the southern coastal province of Hormozgan, announced the IRGC. "It was shot down when it entered Iran's airspace near the Kouhmobarak district in the south."

An IRGC statement said the drone's identification transponder was switched off "in violation of aviation rules and was moving in full secrecy" when it was destroyed.

IRGC commander in chief Brigadier General Hossein Salami warned against any aggression and said the drone's downing carried a "clear message" to the U.S.

The Pentagon denied any of its unmanned aerial vehicles entered Iranian airspace. "There was no drone over Iranian territory," asserted Navy Captain Bill Urban, a U.S. Central Command spokesman.

Thursday's shootdown is the first Iranian attack on a U.S. military vehicle and comes amid the escalating crisis in the Gulf following the bombings of ships in the Gulf of Oman and the Strait of Hormuz over the past month.