(Reuters) - The Buffalo Bills have signed top running back Fred Jackson to a contract extension, the National Football League (NFL) team said on Monday.

Terms of the deal were not disclosed but Buffalo media said Jackson, who had one year remaining on his current contract, agreed to a two-year deal.

Jackson, 31, led the team in rushing for a third consecutive season in 2011, gaining 934 yards on 170 carries. He had six touchdowns in 10 games before suffering a season-ending leg injury.

(Reporting by Gene Cherry in Raleigh North Carolina; Editing by Frank Pingue)