Amy Acton, the Democratic candidate for governor of the US state of Ohio, has called an attack ad against her that features her estranged mother "despicable".

Acton commented on the campaign ad from her Republican opponent, Vivek Ramaswamy, on Wednesday evening, saying: "This is despicable, what he's done".

In the ad Acton's mother, Donna Arthur, says Acton "lied her entire life". But it does not mention that Arthur's husband was charged with raping Acton when she was a child and that Acton and her brother were then removed from Arthur's custody.

Since it launched on Monday, the ad has generated political backlash and cast a national spotlight on the race.

Acton and Ramaswamy are both running to replace outgoing Governor Mike DeWine, a Republican who endorsed Ramaswamy, in the 3 November midterm election.

In a sign that Ramaswamy may have hurt his chances at winning, DeWine has reportedly described the ad as deeply troubling and called for it to be taken down.

"I've never attacked his family. I would never do that," Acton said about Ramaswamy at the campaign stop on Wednesday evening.

"You can see that there are so many people who have experienced trauma and abuse in their lives," she continued, referring to the fallout from the ad.

According to information provided to the BBC by Acton's campaign, the last time she saw her mother was in a courtroom in 1978 after her stepfather was indicted.

Arthur's husband fled town before he could stand trial, was never prosecuted, and died in 2004.

In an ad that Acton released earlier this week, her brother recalled their abuse as children and chided Ramaswamy for using sexual assault as "a political talking point".

Ohio Secretary of State Frank LaRose said his office was reviewing complaints about Ramaswamy's ad, which may have initially aired without a legally required disclaimer to tell viewers who paid for it.

Ramaswamy claimed responsibility the day after the ad was released on social media and said his campaign would spend $4m (£3m) to air it across the state.

The editorial board of local Ohio news outlet The Columbus Dispatch endorsed Acton after the ad dropped, describing it as "revolting and unsettling".

On Thursday, former Republican Ohio Congressman Jim Renacci wrote on X: "The floor may have just fallen out from under the Republican campaign for Ohio Governor.

"And any Republican who fails to distance themselves from this ad risks taking on water as well."

MK Pritzker, the wife of Illinois' Democratic governor, JB Pritzker, announced on Wednesday that she would donate $500,000 to help Acton in the election.

President Donald Trump has said: "It's a very unusual situation to have a mother hate a daughter that much.

"But I don't think that has anything to do with Vivek."

Meanwhile, Vice-President JD Vance has said he would like fellow Republicans to stop "whining" about the ad and that he was "a little bit disgusted" by criticism from members of his own party.

David Lublin, a professor from American University's School of Public Affairs, told the BBC that attack ads are not new in US politics but said "they have become more intense".

He suggested Ramaswamy's ad could be an indication that his campaign is desperate to swing momentum in his favour.

A poll by VoteHub, external released on Thursday suggested Acton was leading Ramaswamy by 1%, within the margin of error, and noted the surveys were done before the ad.

If Acton wins, she would be the first Democrat elected as Ohio governor in two decades.