Out: Adm Fallon denied reports of a rift with George W Bush over Iran
The Pentagon has appointed a temporary replacement for the commander of US forces in Iraq and Afghanistan who retired early amid controversy.
Admiral William Fallon quit on 11 March - a year after taking the job - blaming public perceptions of a rift with US President George W Bush.
A magazine article had said Adm Fallon was opposed to military action on Iran.
Lt Gen Martin Dempsey assumed interim command of US Central Command (CentCom) in a ceremony at a Florida air base.
Deputy at CentCom since August 2007, he will serve as acting commander until Mr Bush finds a permanent replacement.
In: Lt Gen Dempsey took over saying his command was at war
US Defence Secretary Robert Gates said: "Though this is an unexpected assignment for Lt Gen Dempsey, I am confident he is prepared to lead CentCom for as long as necessary."
Adm Fallon had called the article in Esquire magazine "poison pen stuff" and denied policy differences with the White House.
But analysts say he had infuriated the Bush administration with comments like those to al-Jazeera TV last year, when he said he did not expect war with Iran.
CentCom covers an area from the Horn of Africa into central Asia and includes the US operations in Iraq and Afghanistan.