The precariousness of the moment was compounded by widespread uncertainty about the president’s decision-making process, which he detailed Friday in tweets and statements that drew scrutiny from even his own aides.

Early in the day, the president said he called off the attack at the last minute because it would have killed 150 people in retaliation for the downing of the drone. “We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die,” he tweeted.

But administration officials said Trump was told earlier Thursday how many casualties could occur if a strike on Iran were carried out and that he had given the green light that morning to prepare the operation.

The confusion reinforced concerns about the Trump administration’s credibility at a time of military crisis.