Petraeus to lead CIA, Panetta to head Pentagon
US President Barack Obama has nominated Gen David Petraeus, the US head of international forces in Afghanistan, as the new CIA director and has named the agency's chief as head of the Pentagon.
CIA director Leon Panetta should take over as the next defence secretary when Robert Gates retires in late June.
"Leon appreciates the struggles of American troops," Mr Obama said.
Gen Petraeus's job will be filled by Marine Corps Lt Gen John Allen. The Senate must still confirm the changes.
Announcing the most sweeping shake-up of top security officials since he took office, Mr Obama also named Ryan Crocker as the next US ambassador to Afghanistan.
"These are the leaders that I've chosen to help guide us through the difficult days ahead," Mr Obama said with Mr Gates, Mr Panetta, Gen Petraeus and other officials standing next to him at the White House.
'Unity of effort'
Mr Obama said that after nearly 40 years in uniform, Gen Petraeus would retire from the US army and step into his new role at the CIA in September, pending Senate confirmation of the new positions.
The announcement comes less than a year after Gen Petraeus took over responsibility for leading Nato forces in Afghanistan from Gen Stanley McChrystal.
"I will look to them and my entire national security team for their counsel, continuity and unity of effort that this moment in history demands," Mr Obama said of his newly nominated staff.
Mr Obama said Mr Gates, who was first appointed as defence secretary by George W Bush in 2006, had "more than earned the right to return to private life".
Gen Petraeus will be replaced in Afghanistan by Lt Gen Allen, currently deputy head of US Central Command - the command unit covering central Asia and the Middle East.
Lt Gen Allen and Mr Crocker will not fill their new roles immediately but will step into the positions over the summer.
"The challenges are formidable and the stakes are high. 9/11 came to us out of Afghanistan. Our enemy must never again have that opportunity," said Mr Crocker.
Senator John Kerry, chairman of the Senate Foreign Relations committee, praised Mr Obama's decision to move Gen Petraeus to the CIA.
"General Petraeus is simply among the very best military leaders of his generation. He knows first-hand the life and death importance that good intelligence plays in protecting the security of the United States."
Mr Kerry also noted Mr Panetta's "extraordinarily deep institutional knowledge" of Washington.
Republican Senate Minority Leader Mitch McConnell said Mr Obama was "to be commended for choosing competence and continuity" in nominating Gen Petraeus and Mr Panetta for their respective roles.
Mr Panetta, a 72-year-old Democrat from California, served as chief of staff to President Bill Clinton between 1994 and 1997 and took over at the CIA in February 2009.
Prior to those positions, he served as director of Mr Clinton's Office of Management and Budget.
Meanwhile, Afghanistan's spring fighting season is ramping up, testing Nato and Afghan national army territorial gains.
"Today we are a nation at war, and job one will be to ensure that we remain the strongest military power in the world, to protect that security that is so important to this country. Yet this is also a time for hard choices," said Mr Panetta.
In July, the US is expected to begin what US President Barack Obama has called a "significant" withdrawal of troops from Afghanistan, turning over security duties to Afghan military forces.
As of February, more than 1.4m people were serving in the US armed forces.