WASHINGTON (Reuters) - Democratic Senator Jay Rockefeller of West Virginia will announce later on Friday that he will not seek a sixth term in the Senate in 2014, according to a Senate Democratic source.

Rockefeller, 75, is chairman of the Senate Commerce, Science and Transportation Committee. He is scheduled to make an announcement at 11 a.m. EST (1600 GMT) in Charleston, West Virginia, about his future plans, according to his office.

(Reporting by Richard Cowan; Editing by Vicki Allen)