Washington (CNN) Iowa Republican Sen. Joni Ernst is calling on President Donald Trump to send a stronger message against domestic abuse after the resignation of two White House aides.

"I think (President Trump) needs to send a stronger message, a stronger message," Ernst told CNN's John Berman on Tuesday. "We need to allow women and men that have been abused to come out, make sure their stories are heard and believed."

Former staff secretary Rob Porter and speechwriter David Sorensen, who both deny the allegations against them, resigned last week.

Trump told reporters on Friday that Porter's departure was "very sad" and that "he did a very good job while he was in the White House." The President did not express any sympathy for the women Porter allegedly abused, instead focusing on Porter's claim of innocence.

On Saturday, the President took to Twitter to lament that "lives are being shattered and destroyed by a mere allegation," putting himself at odds with the sharp change in how society responds to women's allegations of abuse.

"We need to send a very clear signal" that abuse "won't be tolerated and it won't be tolerated with our employees," Ernst said.

Porter resigned last Wednesday after the allegations surfaced the day before. CNN reported that some of Trump's top aides, including chief of staff John Kelly, knew by last fall that Porter was having difficulty obtaining a security clearance and that his ex-wives claimed he had abused them.

"I'm extremely disappointed in this situation. Abuse is never OK," Ernst said.

She added that she's glad the women have come forward and that she believes them.