NEW YORK, Dec 26 (Reuters) - Fitch Ratings on Wednesday said it may cut its ratings on certain residential mortgage-backed securities insured by MBIA Inc, Ambac Assurance Corp, FGIC Corporation and Security Capital Assurance.

Fitch said it may cut 87 MBIA-insured mortgage bonds, 64 Ambac-insured bonds, 35 FGIC-insured bonds and 19 SCA-insured bonds.

The rating actions follow Fitch's recent warnings that it may cut the top "AAA" ratings of MBIA, Ambac Assurance Corp, FGIC Corporation and Security Capital Assurance.

Fitch has said it is concerned about the bond insurers' exposure to deteriorating mortgage-related investments.

Analysts have said the insurers' exposure to subprime mortgages may reaccelerate the U.S. credit downturn.

The growing fears center on the insurers' guarantees on complex debt to mortgages. Insurer downgrades could spark a ripple effect of further cuts of securities they insure.

A detailed list of the affected RMBS bonds is available on the Fitch Ratings website at www.fitchratings.com.

(Reporting by Neil Shah; Editing by Diane Craft)