WARSAW, Poland (AP) — A Russian prankster posing as the U.N. secretary-general managed to reach Poland's president on the telephone and rendered him speechless with questions about Ukraine, Russia and his reelection on Sunday.

The prankster, Vladimir Kuznetsov, known as Vovan, posted a recording of the 11-minute call on YouTube. President Andrzej Duda's office confirmed Wednesday that it was authentic.

At various points in the conversation, conducted in English, Duda sounds surprised at the line of questioning but still refers to the impostor as "Your Excellency."

Duda tweeted Wednesday that h...