WASHINGTON (AP) — The United States abruptly called off preparations for a military strike against Iran over the downing of a U.S. surveillance drone, a U.S. official said, while Iran claimed Friday it had issued several warnings before shooting down the drone over what it said was Iranian territory.

The Trump administration offered no immediate public account of the thinking behind the last-minute halt in U.S. preparations for retaliation, amid sharply escalating tensions between the two countries . A U.S. official, who was not authorized to discuss the operation publicly and spoke on condition of anonymity, said the targets would have included radars and missile batteries.

The swift reversal was a reminder of the serious risk of military conflict between U.S. and Iranian forces as the Trump administration combines a "maximum pressure" campaign of economic sanctions with a buildup of American forces in the region. As tensions mounted in recent weeks, there have been growing fears that either side could make a dire miscalculation that led to war .

On Friday, the head of Iran's Revolutionary Guard's aerospace division told Iranian state television that Iran had given repeated warnings before launching a missile at the U.S. military surveillance drone.