CIA opens investigation in Petraeus scandal

The CIA has launched an internal inquiry following the resignation of its director David Petraeus, who confessed to an extramarital affair, a spokesman for the US intelligence agency said Thursday.

The US President says disgraced CIA chief David Petraeus posed no threat to national security.

"If there are lessons to be learned from this case we'll use them to improve. But we're not getting ahead of ourselves -- an investigation is exploratory and doesn't presuppose any particular outcome," he said.