Kathryn Smith becomes NFL's first full-time female coach

Kathryn Smith has spent more than a decade working in American Football

American football team the Buffalo Bills have become the first in the National Football League (NFL) to appoint a full-time female coach.

Kathryn Smith has been appointed to the role of quality control-special teams coach for the Bills.

Smith had previously worked as an administrative assistant for the team.

"She certainly deserves this promotion based on her knowledge and strong commitment," said head coach Rex Ryan in a statement.

"She has proven that she's ready for the next step, so I'm excited and proud for her with this opportunity.''

Ryan said he had spoken about the move to Arizona Cardinals head coach Bruce Arians, who last year appointed Jen Welter to a pre-season coaching role.

He also cited another step towards gender equality in US sports, National Basketball Association side the San Antonio Spurs' appointment of a female coach.

Smith has also spent 12 years working for another NFL side, the New York Jets.

Quality control coaches analyse other teams ahead of games, and the role is seen as a step towards more senior positions.

Bills players have been quick to welcome Smith to the new role.

"Congrats to Coach Kathryn Smith! Welcome aboard! This is a big deal people!" tweeted MarQueis Gray.