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Under pressure, Newt Gingrich arranged the release of a contract Monday night showing the Federal Home Loan Mortgage Corp. paid his consulting firm a $25,000 monthly retainer fee in 2006, for a total of $300,000.

The agreement calls for "consulting and related services" but makes no mention of lobbying.

Gingrich has likened his work for the federally backed mortgage giant known as Freddie Mac to that of a historian, and later a strategic adviser. His top rival for the Republican presidential nomination, Mitt Romney, says he was lobbying.

Monday's disclosure touched off fireworks between the two contenders during a prime-time debate.

"This contract proves you were not a historian. You were a consultant," Romney said. "And you were hired by the chief lobbyist of Freddie Mac."

Gingrich chafed at the suggestion he was "influence peddling" and turned the issue back on his opponent.

"Gov. Romney has done consulting work for years," the former House speaker said. "I've never suggested his consulting work was lobbying."

Gingrich's work for Freddie Mac was disclosed long ago, but controversy has flared in the 48 hours since he trounced Romney in the South Carolina Republican presidential primary. The contract with Gingrich's former firm listed Freddie Mac's director of public policy — jargon for lobbyist — as the project executive.

Throughout the early voting states, Gingrich has faced questions from voters concerned about his work for Freddie Mac at town halls. A pro-Romney attacked him on the issue in Iowa. Reporters began asking if he would release the contracts in New Hampshire.

The next primary is set for Jan. 31 in Florida, a state particularly hard hit by the housing crisis of 2008, and one where Gingrich's connections with Freddie Mac may carry a political stigma.

The material was released by the Center for Health Transformation, which Gingrich helped create, and has since sold. The Center for Health Transformation and the Gingrich campaign share a lawyer, Stefan Passantino. He did not return a phone call seeking comment.

Its disclosure came about two hours before a campaign debate in Tampa, and the timing suggested Gingrich was hoping to blunt any attack Romney might make at the event.

Romney has been ramping up criticism for not making the details public sooner. Gingrich said it wasn't only up to him because he no longer controls the firm named in the contract and confidentiality clauses were at play.

The disclosure came amid a volley between the Romney and Gingrich campaigns about who is hiding information voters may want. After facing pressure himself, Romney intends to release some tax records on Tuesday, about a week after Gingrich made his tax returns public.

Gingrich has said previously that firms he ran received about $1.6 million from Freddie Mac for consulting services over several years, and he personally pocketed $35,000 a year. Only the contract covering 2006 was released.

A person who worked closely with Freddie Mac during the years Gingrich was receiving money said Monday night that the former House speaker was employed by the company from 1999 to 2002 by the company's then-chief political executive to review policy proposals created in the hope they would make Freddie Mac more appealing to Republicans.

The official, who spoke on condition of anonymity because of fear of retaliation, said that Gingrich was hired again in 2006 by the company's new chief political executive Hollis McLoughlin — he still works there — to speak and write on the benefits of Freddie Mac. He was paid $300,000 for 2006, and received some additional money in 2007.

In all, he was employed by the political arm of the company for approximately $1.7 million for the sole purpose of convincing fellow Republicans that Freddie Mac was a force for good in America. The person who provided the information on Gingrich's employment pointed to the open-ended nature of the 2006 contract that was released Monday.

Romney's campaign said it wasn't satisfied with only the contract. "He's got to come clean on Freddie Mac. He put out a contract today for a single year even though he's been providing services to Freddie Mac for multiple years," said senior Romney adviser Eric Fehrnstrom. "That contract raises more questions than it answers."

Gingrich spokesman R.C. Hammond said there are no plans for additional disclosures.