Former House Speaker Newt Gingrich says his victory in the South Carolina Republican presidential primary shows people want a nominee who's going to "shake up Washington."

The Georgia Republican renews his attack on opponent Mitt Romney, accusing the former Massachusetts governor of saying things "he knows are false" about Gingrich's record as a paid consultant for mortgage giant Freddie Mac.

Gingrich tells ABC's "Good Morning America" he's comfortable with releasing details of his contract with Freddie Mac and that his lawyers are working on it.

He acknowledges that some key players in the party don't want to see him win the nomination, but he also seems to be enjoying the attention. Gingrich says, "I think you're going to see the establishment go crazy in the next week or two."