(Melina Mara/The Washington Post)

Environmentalists have seized on a comment Vice President Biden made while working a rope line in Columbia, S.C., on Friday, in which he told an activist he is "in the minority" within the administration when it comes to opposing the Keystone XL pipeline.

Elaine Cooper, who serves on the executive committee of the Sierra Club's South Caroline chapter, said in an interview Wednesday that Biden shared his thoughts with her during Rep. James Clyburn's (D-S.C.) annual fish fry.