A 3-year-old boy and 2-year-old girl died early Monday after they had difficulty breathing inside their Van Cortlandt Park South home, police say.

Police say they responded to a 911 call for two children who were having difficulty breathing at the Amalgamated Park Reservoir Houses around 1:15 a.m.

The two children, Olivia and Micha Gee, were unconscious and unresponsive. They were transported to Montefiore Medical Center where they were later pronounced dead.

Both children had a history of asthma, according to police, who added that neither showed signs of trauma.

"It had to have been an accident," says neighbor Aaron Olshan. "This is the most lovely family you would ever see, and they're all close."

Charles M. Zsebedics, head of the housing co-op, says the children's grandmother is the director of education at the complex. 

"We're all shaken," Zsebedics says. "I'm shaken. We don't know what to think of this."

The toddlers' mother and her boyfriend were being questioned by police, investigators say.