Firefighters are without doubt some of the toughest people on the planet - but as one scene from an upcoming documentary has shown, they will do anything to save a life.

BURN: One Year on the Front Lines of the Battle to Save Detroit follows the lives of the American city's firemen, and one scene in which two dying dogs are saved using an officers oxygen mask have become an online sensation.

In the scene, firefighters attending a blaze in a house are approached by a young man who asks if they have fetched his dogs out.

The officers go back into the burning building, and return with the unconscious dogs. One of the firemen gives them Oxygen from his mask, and remarkably the animals come to almost immediately.

The documentary's makers are still raising funds in order to finish production and release the film.