A national women's rights group is calling for prominent companies including Papa John's and Nationwide to suspend their relationships with Broncos quarterback Peyton Manning, after allegations of a sexual assault against him from 20 years ago resurfaced.

"When institutions like the University of Tennessee tacitly condone violence against women by ignoring cases of sexual assault by student-athletes, it perpetuates a dangerous culture of violence that ultimately hurts women everywhere," Nita Chaudhary, co-founder of UltraViolet, said in a release.

"Nationwide Insurance and Papa John's Pizza must show their customers that they will never stand for sexual violence -- and suspend their relationships with Manning pending further investigation."

A women's rights group urged sponsors to suspend ties to Peyton Manning while sexual assault allegations are investigated. Kirby Lee/USA TODAY Sports

Manning was alleged to have placed his genitals on the face of a female trainer in 1996, when he was a player at the University of Tennessee. The trainer, Jamie Naughright, filed a complaint and later settled the case with the university.

The allegation against Manning resurfaced last week when six unnamed women filed suit against Tennessee, claiming the school is fostering a hostile environment for women. Manning is not being sued or accused of anything in the latest suit. Rather, the incident was included in a list of examples used to help bolster the women's claims.

Manning has made no public comment on the issue.

"While it is outrageous that the University of Tennessee chose to turn a blind eye to sexual violence by student athletes like Manning, it would be flat-out unacceptable for the NFL and major companies like Nationwide Insurance and Papa John's Pizza to continue to stand with Manning in light of emerging evidence," Chaudhary said in the statement. "The NFL should thoroughly investigate this incident before allowing Manning to play or work in (the) NFL again."

UltraViolet has previously called for the resignation of NFL commissioner Roger Goodell after his initial handling of the Ray Rice domestic violence incident in 2014.