The current head of US military operations in Afghanistan, General David Petraeus, is become the new director of the CIA, it was reported today.
He will replace Leon Panetta at the spy agency's helm.
Mr Panetta is to be nominated later this week to take over from Robert Gates as US defense secretary.
The positions would require Senate confirmation, suggesting the changes would not occur for some weeks or even months.
Mr Obama will also announce that Lt Gen John Allen will replace Gen Petraeus as Afghanistan commander, and that diplomat Ryan Crocker will be the next US ambassador in Afghanistan, replacing current ambassador Karl Eikenberry, who is expected to depart in the next few months.
A presidential reshuffling of top national security jobs has been an object of speculation for weeks.
Mr Gates, the current Pentagon chief and a former CIA director, had made clear that he planned to step down as defense secretary this year.
Mr Panetta, who turns 73 in June, is a long-standing Democratic Party figure who could prove closer to Mr Obama than Mr Gates, who was appointed by former president George W Bush and proved to be a maverick under both administrations.
Gen Petraeus (58), is a popular figure credited with pulling Iraq from the brink of civil war after the 2003 US invasion before he assumed command of US and Nato forces in Afghanistan.
Before word of the reshuffle broke, some Washington insiders suggested a Petraeus-for-Panetta swap could come as Mr Obama gears up his 2012 re-election campaign.
They suggested the White House wanted a high-profile position for Gen Petraeus to ensure he would not be tapped by Republicans to challenge Mr Obama.