New York Congressman Anthony Weiner said on Wednesday that he did not send a lewd photo over his Twitter account but cannot be sure that the photo was not of him.

It certainly doesn't look familiar to me, but I don't want to say with certitude to you something that I don't know to be the certain truth, Weiner told CNN in an interview.

I didn't send any twitter picture, he said, adding that the photo might have been manipulated.

Weiner has said his account was hacked when a lewd photo of a man in bulging boxer briefs was tweeted to a 21-year-old female college student in Washington state over the weekend.

This seems like it was a prank to make fun of my name, Weiner said. When you are named Weiner, that happens a lot.

Weiner's office told Reuters on Tuesday that the New York congressman, who has a high profile as an advocate of liberal causes, had hired an attorney to advise him on whether or not he could press criminal charges as a result of the alleged hack of his Twitter account.

This is not a national security matter, Weiner said. We're not making a federal case out of this....I'm not sure it rises -- no pun intended -- to that level, he said.

Weiner said that the law firm he hired has an Internet security firm that is investigating how his account was hacked.

He declined to say whether there actually was a photo of him in his undies like the one sent to the student.

This is part of the problem with the way this has progressed, and one of the reasons I was perhaps, forgive me, a little stiff yesterday, Weiner told reporters on Capitol Hill.

The student, Gennette Cordova, issued a statement to the New York Daily News that denied she personally knew Weiner but said, I am a fan.

Weiner had tens of thousands of followers on twitter before the weekend's incident. In contrast, Weiner was following 198 people.

(Reporting by Wendell Marsh; Additional Reporting by Andy Sullivan; Editing by Greg McCune)

(This story was corrected in the headline to show Rep. Weiner not Republican)