WASHINGTON -The top U.S. military commander for the Middle East resigned Tuesday amid speculation about a rift over U.S. policy in Iran.

Defense Secretary Robert Gates said that Adm. William J. Fallon had asked for permission to retire and that Gates agreed. Gates said the decision, effective March 31, was entirely Fallon’s and that Gates believed it was “the right thing to do.”

Fallon was the subject of an article published last week in Esquire magazine that portrayed him as opposed to President Bush’s Iran policy. It described Fallon as a lone voice against taking military action to stop the Iranian nuclear program.

Fallon, who is traveling in Iraq, issued a statement through his U.S. headquarters in Tampa, Fla.

“Recent press reports suggesting a disconnect between my views and the president’s policy objectives have become a distraction at a critical time and hamper efforts in the Centcom region,” Fallon said.

“And although I don’t believe there have ever been any differences about the objectives of our policy in the Central Command area of responsibility, the simple perception that there is makes it difficult for me to effectively serve America’s interests there,” Fallon added.

Gates described as “ridiculous” any notion that Fallon’s departure signals the United States is planning to go to war with Iran. And he said “there is a misperception” that Fallon disagrees with the administration’s approach to Iran.

“I don’t think there were differences at all,” Gates added.

Fallon has had a 41-year Navy career. He took the Central Command post on March 16, 2007, succeeding Army Gen. John Abizaid, who retired. Fallon previously served as commander of U.S. Pacific Command.

Gates said that until a permanent replacement is nominated and confirmed by the Senate, Fallon’s place will be taken by his top deputy, Army Lt. Gen. Martin Dempsey.

The secretary called Fallon a very able military strategist and said his advice will be missed at the Pentagon.

“I think this is a cumulative kind of thing,” said Gates, speaking of the circumstances leading up to Fallon’s decision. “It isn’t the result of any one article or any one issue.”

“As I say, the notion that this decision portends anything in terms of change in Iran policy is, to quote myself, ‘ridiculous,’ ” he said.