Secretary of Defense Robert Gates speaks during a news briefing on the new Nuclear Posture Review at the Pentagon in Washington April 6, 2010. REUTERS/Yuri Gripas

WASHINGTON (Reuters) - Iran is challenging U.S. naval power in the Middle East with an array of offensive and defensive weapons, U.S. Defense Secretary Robert Gates said on Monday.

“Iran is combining ballistic and cruise missiles, anti-ship missiles, mines, and swarming speedboats in order to challenge our naval power in that region,” Gates told a conference of U.S. Navy advocates outside Washington.

Gates did not elaborate on the perceived Iranian threat.

His remarks were part of a review of budget and shipbuilding trade-offs facing the U.S. Navy and Marine Corps, and they came the same day that Iranian President Mahmoud Ahmadinejad spoke at the United Nations in New York.

Gates said last week he was satisfied with the pace of U.S. planning to thwart Iran’s nuclear program, which the United States and other Western nations suspect is aimed at developing atomic weapons. Iran says the program is to generate electricity.

Pentagon planners have been drawing up military options in case President Barack Obama opts to use force against Tehran. U.S. leaders repeatedly have said that would be an option of last resort if sanctions and diplomacy failed.

Iran’s naval forces include several anti-ship coastal defense missile batteries as well as submarines, missile boat and naval aviation units, according to an unclassified version of a Pentagon report on Iranian military power sent to Congress last month.