PUEBLO, Colo. — Two sisters, ages three and five, and their 17-year-old female baby sitter drowned in a swimming pool in a southern Colorado mobile home park, police said Monday.

Pueblo police were investigating what led to the drownings but said no foul play was suspected, The Pueblo Chieftain reported.

"I think it's just a horrible tragedy," Capt. Joe Garcia said.

The names of the victims weren't immediately released.

Officers responding to an emergency call shortly after 2 p.m. tried to revive the victims at Pueblo Grande Village, a mobile home park located north of downtown Pueblo, about 105 miles south of Denver.

The Pueblo Police Department says the victims were pronounced dead by the coroner's office.

Neighbors appeared shaken as police investigated the scene.