“As we discussed with your counsel, divestiture is the way to resolve these conflicts,” the office wrote on Twitter, revealing legal advice that would normally be confidential and adding in a separate post: “Bravo! Only way to resolve these conflicts of interest is to divest. Good call!”

In fact, Mr. Trump had made no such commitment, at least publicly.

In a series of early-morning posts on Twitter, Mr. Trump said he would separate himself from the operations of his vast global business empire.

Mr. Trump provided few details in his posts and did not say whether he would divest his assets.