A spokeswoman for President Bush says the head of the U.S. Central Military Command is not being forced to resign, despite reports that Admiral William Fallon disagrees with the president's policy on Iran.

White House spokeswoman Dana Perino Wednesday, said President Bush welcomes robust and healthy debate and is grateful for the admiral's service.

Fallon was on a trip to Baghdad Tuesday when he announced he is resigning at the end of the month. That announcement followed a report in Esquire magazine that said Fallon disagrees with the Bush administration on whether to take military action against Iran for failing to stop its nuclear program.

Admiral Fallon denied that his opinion differs from the president's, but he said the perception of discord makes it difficult for him to serve effectively.

The Navy admiral is in charge of managing the wars in Afghanistan and Iraq and U.S. military engagement throughout the Middle East, Central Asia and East Africa.

At the Pentagon Tuesday, Defense Secretary Robert Gates called "ridiculous" the notion that Fallon's resignation signals the Bush administration is preparing to go to war with Iran. Gates said the admiral made the decision to step down on his own.

Senate Majority Leader Harry Reid, a Democrat, expressed concern that the departure is an example that dissenting opinion is not welcome in the Bush administration.

Admiral Fallon's resignation takes effect March 31, marking the end of more than four decades of service. He will be replaced temporarily by his deputy, Lieutenant General Martin Dempsey.

Some information for this report was provided by AFP.