With risks considerably reduced that the stabilizing U.S. economy could suffer a relapse, the Federal Reserve decided to continue its emergency long-term security buying programs as promised, documents released on Wednesday showed.

Policy-makers envisioned only a gradual upturn in economic activity accompanied by subdued inflation after a deep recession and devastating financial meltdown, minutes of their August 11-12 meeting said. In light of that, they said it was most likely that they would hold benchmark rates at very low levels for an extended period of time.

With a sluggish recovery likely, the Fed decided that neither expansion nor contraction of asset purchase was warranted.

Policy-makers discussed adding adjustable rate mortgages to those eligible for purchase under the program, the minutes showed. Some held the view that tapering off purchases of mortgage-related debt could be helpful as those programs neared completion. No decision was made in either case.

(Reporting by Mark Felsenthal; Editing by Andrea Ricci)