GOP presidential candidate Newt Gingrich began receiving payments from Freddie Mac in 1999 under a contract that paid his consulting business $25,000 a month to work with the mortgage giant's chief lobbyist.

Details of the second agreement between Freddie Mac and Gingrich's company, the Center for Health Transformation, were released Tuesday night. The contract specifically excluded lobbying services.

Gingrich left the Center for Health Transformation last year as he prepared to run for president.

His work with Freddie Mac has received renewed scrutiny as GOP rival Mitt Romney has criticized the arrangements as influence peddling by the former House speaker. Gingrich denies every working as a lobbyist and has blasted Romney, saying he has mischaracterized his work in a desperate attempt to regain momentum in the Republican presidential race.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)