The suicidal Long Island mom accused of killing her 2-year-old twin daughters choked the life out of them, authorities revealed Wednesday as she was indicted on murder charges.

Tenia Campbell, 24, of Medford pleaded not guilty during her arraignment in a Suffolk County criminal court.

Campbell had admitted to police that she killed her children, Jasmine and Jaida, on June 27 with her “bare hands” in Montauk.

“I killed them. The girls are dead in the car with me. I killed them with my hands. I can’t kill myself, so someone is going to find me and I’m going to jail,” Campbell had told police, prosecutor Kerriann Kelly said Wednesday after the arraignment.

An autopsy conducted by the Office of the Suffolk County Medical Examiner on the two young girls found the cause of death to be homicidal violence consistent with manual asphyxia, it was revealed Wednesday.

“There are probably a number of different ways that that could occur but basically it’s covering an individual’s mouth and nose so they are no longer getting any oxygen, whether that’s by hand or a pillow or in some other manner,” Kelly told reporters following Campbell’s arraignment.

Campbell, who wore a green prison uniform, was remanded without bail and remained on suicide watch.

If convicted, she faces life in prison without parole.

Campbell’s defense attorney, John Halverson, said outside court that his client’s “mental disorder is going to be the subject of my defense,” and noted that Campbell has a history of mental illness.

“Any mother alleged to harm her own children is obviously not in the right state of mind,” Halverson said.

Campbell and her two lifeless daughters were found inside the family minivan by cops on June 27 after Campbell’s worried mother called 911, saying that Campbell was threatening to kill herself and the twins, police have said.

The children were found in cardiac arrest inside the 2001 Chrysler Town and Country minivan in their car seats.

Police took Campbell into custody and attempted to resuscitate the two children, who were taken to Stony Brook Southampton Hospital, where they were pronounced dead.

Campbell’s family members showed up in court for her arraignment.

“She’s a beautiful person and she don’t deserve this even though what happened, happened,” said Campbell’s aunt Cindy Campbell. “God allowed what happened for a reason. And all those negative comments people are making, I am going to pray for them because she’s a beautiful person.”

Suffolk County District Attorney Timothy Sini called the case “extremely tragic” in a statement.

“Especially as a parent, the alleged actions of this defendant are incomprehensible,” Sini said, adding, “While nothing can bring those girls back, we will seek justice on their behalf.”

Campbell’s next court date is slated for Aug. 7.