Sophia Hines, 40, originally from Philadelphia, was arrested after her 7-month-old son and 3-year-old daughter were found dead in an apartment in Miramar, Florida, on Wednesday.
When the police arrived, a parent and a relative led them to the back of the house, where they found the two unresponsive children.
The officers performed CPR on the children until fire rescues crews arrived and declared them dead. Hines was then arrested and has since been booked into Broward County Jail.
Police say that Hines admitted suffocating her 7-month-old son and 3-year-old daughter by holding a sheet over their mouths in a bedroom in a small rental house.