But the company offered no explanation as to how the passwords had been obtained, how they ended up being earlier this week, and what other data might have been compromised.

In a somewhat , LinkedIn director Vicente Silveira this afternoon said that LinkedIn had "learned" about 6.5 million passwords being posted on a hacker site, but then neither confirmed nor denied that number.

Instead, he merely noted that most of the passwords on the list appeared to remain hashed and hard to decode. "But unfortunately a small subset of the hashed passwords was decoded and published," Silveira said.

This is the first time that LinkedIn has alluded to 6.5 million passwords being compromised. Yesterday, in its on the incident the company had merely noted that "some" hashed passwords might have been compromised.

Silveira's blog post does not make clear if the hackers who accessed the passwords had also managed to access the associated email logins. Rather, Silveira merely noted that LinkedIn has so far not seen any evidence of LinkedIn email IDs being publicly posted online. "Nor have we received any verified reports of unauthorized access to any member's account as a result of this event," he wrote.