FILE PHOTO: U.S. Secretary of State Mike Pompeo speaks during a news conference after the U.S.-Canada ministerial meeting at the State Department in Washington, U.S., December 14, 2018. REUTERS/Jim Young

BRASILIA (Reuters) - The United States wants an explanation of why Russia detained a retired U.S. Marine on spying charges in Moscow and will demand his immediate return if it determines his detention is inappropriate, Secretary of State Mike Pompeo said on Wednesday.

Speaking in Brasilia the day after Brazil’s new president Jair Bolsonaro was inaugurated, Pompeo said the U.S. government hoped to gain consular access to Paul Whelan within the next few hours following his arrest in Moscow.

(The story corrects first paragraph to reflect demand for retired Marine’s return is conditioned on Russia’s explanation.)