WINDSOR, Ont. - A premature baby was in critical condition Wednesday while its sibling was faring much better in hospital after their mother gave birth to the twins on a snow covered street, much to the surprise of police who came upon the family.

As sleet fell just before midnight Tuesday, two Windsor police officers discovered a 27-year-old woman in distress in this southwestern Ontario city.

"Their initial reaction was that she was probably the victim of some kind of assault," said Deputy Chief Jerome Brannagan, who noted there was a considerable amount of blood on the woman.

After talking to the "hysterical" woman, a very different picture emerged for the officers.

"She revealed to them that she was pregnant, and lifted up her shirt, and revealed a newborn child," Brannagan said.

About three minutes later, the unidentified woman gave birth to a second child.

"(The officers) were quite surprised to say the least."

The twins' 42-year-old father arrived shortly afterward and was also quite upset, Brannagan said.

"Our people just tried to calm everybody down."

The mother and children were taken to Windsor Metropolitan hospital, where one of the newborns was reported to be in critical condition.

The Children's Aid Society was contacted to investigate, but there is no criminal investigation underway, Brannagan added.

"Anything that comes up in the (CAS) investigation that would be relative to any police action, they would certainly notify us."

While trained to deal with such an incident, it's an unprecedented situation for most Windsor police officers, Brannagan said.

"I've been here 30 years. I don't know anybody who's had to deal with anything like this before," he said.

"This is more unusual where it was immediate and it was very traumatic to everyone involved."