Fitch Ratings on Monday lowered its outlook on U.S. credit rating to "negative", warning to slash U.S. triple-A credit rating if policy-makers failed to agree on a cut plan in 2013 to address the country's ballooning budget deficit.

The ratings agency revised its outlook on the U.S. long-term credit ratings from "stable" to "negative", citing the failure of U.S. congressional "super committee" in agreeing on a 1.2-trillion- dollar deficit-reduction plan last week.

"The negative outlook reflects Fitch's declining confidence that timely fiscal measures necessary to place U.S. public finances on a sustainable path and secure the U.S. triple-A sovereign rating will be forthcoming," the ratings agency said in a statement.

The so-called "super committee" of six Democrats and six Republicans last week declared that they couldn't reach an agreement by the deadline on reducing deficit, triggering an automatic deficit cuts program of at least one trillion, which would be evenly split between domestic and military cuts over next decade.

Rivals rating agency Standard & Poor's maintained an AA+ rating for U.S. with a negative outlook, while Moody's Investors Service gave the U.S. a triple-A credit ratings, also with a negative outlook. After super committee's failure, the two agencies said that it would not affect their ratings immediately.