Petraeus sworn in as new CIA chief

Newly retired General David Petraeus was sworn in as CIA director today, taking over at a time when the line between the US spy agency and the military has become increasingly blurred in the fight against Islamist militancy.

Petraeus, who in a storied 37-year Army career rose to become arguably the US military's brightest star, took the oath of office at a White House ceremony led by Vice President Joe Biden.

President Barack Obama enlisted Petraeus to take over at the CIA as part of a major shuffle of his national security team that included Leon Panetta moving from CIA chief to defense secretary as successor to the retiring Robert Gates.

Petraeus is credited with helping to turn around the Iraq war and also set in motion Obama's revamped strategy in Afghanistan aimed at halting the momentum of the Taliban insurgency and laying the groundwork for a gradual U.S. troop drawdown.

Petraeus takes over at the CIA less than a week before the 10th anniversary of the Sept. 11 attacks on New York and Washington that drew the United States into a protracted fight against al Qaeda and its Islamist allies.

Petraeus, 58, was in a civilian business suit for his first day as head of the CIA, considered the top echelon among an array of US intelligence services.

At his retirement ceremony last week, his last day in uniform, Petraeus urged politicians to tread lightly if they plan to slash the military's budget at a time of rising pressures in Washington to tackle deficit woes.