A mother and two of her three young children were fatally stabbed early Wednesday at a motel housing homeless families on Staten Island and police were searching for a 23-year-old man who they suspect killed the three, including his 4-month-old daughter, officials said.

“This is an atrocious crime,” Mayor Bill de Blasio said at a news conference in police headquarters with NYPD Commissioner William Bratton. “I think every parent would share my view that their hearts would break to see children attacked.”

Police suspect the slayings occurred about 8:50 a.m. Wednesday, after a man identified as Michael Sykes of Brooklyn was seen on a surveillance camera entering the room at the Ramada Inn in the Willowbrook section of Staten Island where the victims were stabbed.

Killed in the stabbings were Rebecca Cutler, 26; and her daughters Ziana Cutler, 1, and Maiyah Sykes, 4 months. Maiyah was Sykes’ daughter.

A third daughter, age 2, also was stabbed, but survived and was listed in critical but stable condition Wednesday at Richmond University Medical Center, police said.

Cutler and her children had been living at the Ramada Inn since Dec. 6 rather than being housed in a regular shelter.

advertisement | advertise on newsday

According to police, Sykes and Cutler had a dispute on Tuesday in which Sykes took Cutler’s cellphone.

Investigators were looking into whether Cutler was trying to rekindle a relationship with the father of one of the children. Investigators noted that neither Sykes nor Cutler had any significant criminal history, record of domestic violence or problems with the law.

Chief of Detectives Robert Boyce said surveillance cameras showed Sykes and Cutler going to a nearby deli, apparently for food, about 7:30 a.m., then returning to the motel. Sykes remained in the hallway of the motel, and then entered the room for about four minutes. Police think this is when Cutler and the girls were attacked, Boyce said.

Sykes called a family member about 10:30 a.m. and admitted committing the crimes and threatening to take his own life, Boyce said, adding police found the knife used in the attack.

“We will see if that happens. Right now I would recommend everybody call 911 if they see him,” Boyce said.

The Ramada Inn had overnight security on duty from about 10 p.m. Tuesday to 6 a.m. Wednesday, de Blasio said.

Sykes is believed to have taken a bicycle to the Staten Island Ferry and then took a boat to Manhattan, police said. Sykes, also known by the moniker “Skyes,” lives in Howard Houses in Brooklyn, police said.

Wednesday afternoon, police began moving dozens of shelter residents into a white shuttle bus parked in the driveway of motel. Many of the residents embraced each other before getting onto the bus. Many children and infants were among the shelter residents.

James Sweeting, 52, a brass worker who was a shelter resident at the motel, was at work when he received a call to return to the motel and pack his belongings for relocation. “They called me at my job an hour ago so I had to come,” he said.

“They had security at night but not at the daytime. . . . Actually, I don’t feel that my life was threatened.”

advertisement | advertise on newsday

He said he was at the Ramada Inn for 57 days and had stayed at several other shelters beforehand. “This is the best one I’ve ever had,” Sweeting said.

With Jason Shaltiel