President Donald Trump approved military strikes on Iranian targets in retaliation for a strike on a U.S. drone but later backed away, The New York Times and The Washington Post reported Thursday night, citing multiple administration officials.

The Times quoted a senior administration official as saying the operation was under way in its early stages — with planes in the air and ships in position — when it was called off.

On Friday, White House officials declined to comment on the Times' report. Defense Department officials hadn't commented Thursday night.

No government officials asked The Times to withhold the article, the newspaper said.

The developments came as the United States and Iran continued to fight over whether the high-altitude U.S. surveillance drone had violated Iranian airspace when it was shot down Thursday.

On Friday, a senior official from Iran's Islamic Revolutionary Guard Corps said several warnings were issued before the drone was downed.

"We have had two stages of warnings," Cmdr. Amir Ali Hajizadeh said on state television. "They did not respond."

The aircraft was shot down after the last warning at 3:55 a.m. Thursday (7:25 p.m. ET Wednesday), he said.

The incident has prompted the Federal Aviation Administration, or FAA, to prohibit most U.S. civil aircraft from flying in Iranian-controlled airspace over the Persian Gulf and the Gulf of Oman.

In a Notice to Airmen advisory, the FAA cited "heightened military activities and increased political tensions in the region, which present an inadvertent risk to U.S. civil aviation operations and potential for miscalculation or misidentification."

The notice applies to almost all U.S. carriers and commercial operators.

Other carriers also announced plans to halt flights over the Strait of Hormuz, including Dutch carrier KLM and Australian airline Qantas.

Trump signaled earlier Thursday that the United States was considering options for how to respond to the shooting down of the U.S. drone, an unarmed Global Hawk aircraft that can fly at up to 60,000 feet.

"Iran made a very bad mistake," Trump said. "The drone was in international waters, clearly. We have it documented."

The commander of the Revolutionary Guard Corps, Gen. Hossein Salami, said Thursday that the strike served as a signal that Iran wouldn't back down from threats.

"We have no intention of war, but we are standing strong," he said.

But Navy Capt. Bill Urban, a spokesman for U.S. Central Command, called the strike "an unprovoked attack," saying: "Iranian reports that the aircraft was over Iran are false."

U.S. officials have also blamed Iran for what they said was an attack on two oil tankers in the Gulf of Oman last week. Iran has denied any involvement.

Acting Defense Secretary Patrick Shanahan announced Monday that the United States would send 1,000 additional troops to the region to address what he called air, naval and ground-based threats.