OTTAWA–A top adviser to Hillary Clinton arrived by plane in Ottawa to deliver a speech only to be subjected to intensive interrogation about who he was, what he was going to say and what group he was addressing, the American economist said yesterday.

In a private lunch, Gene Sperling complained that he had been pulled aside by a Canadian border official and questioned in more detail than he had ever experienced in his numerous trips to Canada or dozens of other countries, according to those in attendance.

Many in the luncheon group, which included business people, a United States government official, journalists and organizers of the speaking event, said they were shocked by the extent of the grilling reported by Sperling.

But in public later, the former national economic adviser in the Bill Clinton administration refused to discuss the matter in detail. Choosing his words carefully, he appeared to put it all down to an overzealous Canadian border official.