The US President Barack Obama has nominated Gen David Petraeus, the US head of international forces in Afghanistan, as the new CIA Director. The current CIA Chief Leon Panetta will take over as the next Defence Secretary when Robert Gates retires in late June. Announcing the most sweeping shake-up of top security officials since he took office, President Obama also named Ryan Crocker as the next US Ambassador to Afghanistan. President Obama said that after nearly 40 years in uniform, Gen Petraeus will retire from the US army and step into his new role at the CIA in September, pending Senate confirmation of the new positions.