President Trump has blasted Lindsay Clancy's killing of her three young children after the Massachusetts mother's murder trial collapsed.

Speaking at the White House Friday, Trump said: 'It's a shame. It's a horrible tragedy. I see what's happened and it looks like it's a hung jury. 

'I think the judge has said it's going to be a mistrial, so there's going to be another trial.

'It's a terrible situation. Look, she did a horrible, horrible thing. 

'Can't be worse. But you'll find out what the price to pay is. There'll be a price. It's going to be mental institution or jail or something, but I guess they're going to go through another trial.'

Clancy, 36, faces a retrial after a jury of nine women and three men were unable to agree on whether she was guilty of the murders or manslaughter of Cora, five, Dawson, three and 18-month-old Callan in Duxbury, Massachusetts, in January 2023. 

Judge William Sullivan declared a mistrial at Plymouth Superior Court on Friday afternoon. 

Clancy admits strangling her children with exercise bands but denies it was murder. 

The former nurse said she was overmedicated while suffering from postpartum depression and that the cocktail of drugs she was prescribed brought on psychosis.

She tried to kill herself by jumping out the upstairs window of the home she shared with ex-husband Patrick Clancy in the wake of the killings. 

The [attempt at taking her own life] failed but left Clancy paralyzed and permanently confined to a wheelchair. 

Jurors spent more than 37 hours deliberating five-and-a-half weeks of evidence, with one refusing to side with the others late Thursday and early Friday. 

Clancy's attorney Kevin Reddington sought an emergency order to try and force jurors to enter one final round of deliberations.

A hearing with a justice of Massachusetts' Supreme Judicial Court was held, but quickly ruled in favor of Judge Sullivan's original plan to declare a mistrial.

Prosecutor Tim Cruz has not yet confirmed that he plans to try Clancy again, but a retrial seems likely.

Speaking after the mistrial was declared, he maintained his view that Clancy's killings of her children were cold-blooded, calculated murder. 

The next hearing in the case has been scheduled for September 29.

Prosecutors could opt to try Clancy on identical charges - first and second-degree murder, as well as manslaughter.

They could seek to retry her on less serious charges, likely manslaughter. 

They may also opt to have a judge decide the verdict themselves, rather than put the case to a jury again. 

Clancy's trial attracted international attention.

On Friday afternoon, Reddington suggested it would be impossible to find an impartial panel of jurors to try a case that has attracted international attention.