TEHRAN—Multinational companies that recently made big bets on Iran scrutinized the Trump administration’s decision to revive sanctions on the country for ways to preserve their interests there.

President Donald Trump said he would pull out of a multilateral deal that removed most economic sanctions on Iran in exchange for curbs on its nuclear ambitions. He also promised new U.S. penalties, without providing specifics.

European executives—who plunged back into Iran more quickly than their American rivals after the nuclear pact took effect in 2015—are now reviewing once-heady investment plans there. In some cases, they are weighing contingencies if the new U.S. policy bars their Iran activities.

Executives were still parsing statements from Mr. Trump and other members of his administration late Tuesday. The U.S. Treasury said it would revoke authorization for aviation exports to Iran within 90 days, all but prohibiting big orders Iran placed for Boeing Co. and Airbus SE jets.

Airbus, after securing U.S. government approvals, completed a deal for 100 planes to Iran in late 2016. Three of those aircraft have been delivered. All aircraft were shipped with U.S. licenses that were required because American parts are used on the planes.