Two women who have accused Congressman Eric Swalwell of sending unwanted explicit photos say they are grateful he is facing consequences now and leaving Congress after acting with impunity for years.

Annika Albrecht and Ally Sammarco told the BBC's US partner CBS News they feel vindicated. But Albrecht said there is more to be done.

"For me, justice won't be until he can't ever harm a woman ever again, and he has faced the consequences for the women that he has harmed," she said.

Swalwell, a Democrat, said on Monday that he will resign. He has also dropped out of the California governor's race. He apologised to his wife and supporters for making mistakes but denied claims of sexual abuse.

In a statement, Swalwell has said he is "deeply sorry to my family, staff, and constituents for mistakes in judgement I've made in my past".