Mr. Trump has previously suggested that Britain “should leave,” although he has offered only circumscribed thoughts about the issue, which is expected to affect global markets.

Mr. Trump is expected to arrive in Scotland on Friday, a day after the vote, for a ribbon-cutting at one of his newest golf clubs. It will be his first international trip since he became the presumptive Republican nominee.

Prime Minister David Cameron of Britain, who is urging Britons to vote to stay in the European Union, has been deeply critical of Mr. Trump, describing him as “divisive.” The newly elected mayor of London, Sadiq Khan, the city’s first Muslim mayor, has also criticized Mr. Trump for his proposed ban on Muslim immigrants entering the United States.