Trump kept calling the prime minister of Spain 'president'

President Donald Trump repeatedly called the prime minister of Spain, Mariano Rajoy, "president" during a joint press conference on Tuesday.

The confusion may come from Rajoy's official title - "president of the government" - although it is commonly accepted that the head of Spain's government is known as "prime minister."

Trump called Rajoy president at least three times during their press conference, including during his introductory remarks.

Trump also asked the gathered reporters if there was a question for "the president," pointing at Rajoy. The reporter who asked the next question addressed Rajoy as "prime minister."

The White House also called Rajoy Spain's president in a tweet before the press conference: