A New York woman is accused of stabbing her two young nieces in a bloody rampage while baby-sitting the girls, then calling 911. 

Police said Lisa Turkki, 39, repeatedly stabbed Maeve and Annabel Kelly, ages 7 and 9, at her sister and brother-in-law's house in Katonah, N.Y. house, while the couple attended a concert down the street Saturday night, the Journal News reported.

The house is directly across the street from Martha Stewart's farm.

Police received the 911 call from the house around 9:22 p.m. ET and found the girls in a scene officers called "quite horrible."

"There was a lot of blood in the kitchen area," said Lt. Jeffrey Dickan of the Bedford police.

The girls were both conscious and talking when they were found, he said, and the two kitchen knives that they appeared to have been stabbed with were recovered.

They were in stable condition and improving after surgery on Sunday, Dickan added.

Turkki was outside the house when police arrived and sustained a minor injury to her leg that was possibly self-inflicted, Dickan said. She voluntarily submitted to urine and blood tests and did not appear to be under the influence of drugs or alcohol, he said.

The girls' parents, Joe Kelly, 50, and Eva Kelly, 43, were attending a concert at the Caramoor music center nearby when they were called to the box office at intermission and told to return home, the Journal News reported.

Police said by the time they arrived home, the girls had been taken to the hospital, but neighbors reported hearing screams when they saw the crime scene, the Journal News reported.

Turkki was arraigned on two counts of first-degree assault, both felonies, and is being held at a county jail. The name of her attorney was not on record early Monday. She is due back in court Aug. 5.

The Associated Press contributed to this report.