On Friday afternoon, as word began to leak out that Mr. Petraeus might be leaving his post, a shocked Ms. Feinstein, who chairs the Senate intelligence committee, called Mr. Petraeus to ask what was going on, and questioned whether it was necessary to step down.

WSJ: Petraeus Affair Puts Scrutiny on FBI

Speculation has been growing since Thursday when word first began to leak.

FORBES: Why Is Microsoft's Announcement So Secret?

There is no word on the cause of the leak.

BBC: French Lubrizol factory struggles to stop foul gas leak