An 11-month-old baby and a 3-year-old boy died of stab wounds after their mother was taken into custody for observation Saturday night in New York City, police said.

The children, both boys, were found in a Bronx apartment with multiple injuries to their necks and torso and did not survive after being transported to a hospital, Patrol Borough Bronx Deputy Chief Louis De Ceglie said at a news conference on Saturday night.

Officers and another family member tried to resuscitate them at the scene, he said.

De Ceglie said officers had been dispatched to the scene around 7:20 p.m. in response to reports of a «female acting erratic, but non-violent, unarmed.» Dispatchers were told a woman was trying to burn items in the kitchen, he said.

Once they arrived, he said they «found a 24-year-old female naked inside the apartment on the third floor acting irrationally,» who they later determined was the mother of the children.

She was detained without incident until an ambulance arrived, which took her to St. Barnabas Hospital for evaluation around 7:50 p.m., De Ceglie said.

A family friend told officers that the children were with their father, before she left, she added.

Five minutes later, he said a 911 call reported «two unresponsive, non-breathing babies in the same spot.»

Officers returned to the apartment and found the children, De Ceglie said, adding: «Despite the officers’ best efforts, both children succumbed to their injuries.»

“It’s something they’ll probably have to live with and think about for the rest of their lives, but we have very experienced police officers. I think they are the best and they are able to handle and deal with any situation,” he added.

He said the mother was «in custody and is still under investigation.» The father was not in custody, she added.