Washington: A growing national outcry over sexual harassment has reached the United States Senate after a radio newscaster accused Democrat Al Franken of kissing and groping her without consent during a 2006 USO tour of the Middle East before he took public office.

Franken, who has been mentioned as a possible presidential candidate, almost immediately released an apology to the newscaster, Leeann Tweeden, who said that Franken forcibly kissed her during a rehearsal and groped her for a photo as she slept.

Democratic Senator. Al Franken has apologised a radio anchor accused him of forcibly kissing her in 2006. Credit:AP

"The first thing I want to do is apologise: to Leeann, to everyone else who was part of that tour, to everyone who has worked for me, to everyone I represent, and to everyone who counts on me to be an ally and supporter and champion of women," Franken wrote.

"I respect women. I don't respect men who don't," he continued. "And the fact that my own actions have given people a good reason to doubt that makes me feel ashamed."