SIOUX FALLS, S.D. - Police have arrested two former day care workers in South Dakota who allegedly lifted kids into the air and violently slammed them onto sleeping mats, sometimes stepping on them, according to CBS affiliate KELO. Police say they viewed surveillance video which showed numerous instances of abuse.

31-year-old Teresa Gallagher and 22-year-old Kenedi Wendt were arrested on 25 counts of abuse or cruelty to a minor. The children involved are reportedly 3 and 4 years old.

"There were times when their heads were banged around; they were yanked up by their arms," said Sioux Falls Police Public Information Officer Sam Clemens, the station reports.

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Authorities began investigating the Little Blessings Daycare in western Sioux Falls last month after the parents of one boy filed a report in late February, reports KDLT. The boy said a worker banged his head on a mat while he was sleeping, according to KELO.

KDLT reports police reviewed surveillance video between Feb. 14 and Feb. 23 that they say shows the two employees abusing most of the children in the room during nap time. The two women were immediately fired.

Clemens said that none of the children required medical attention, but some had complained of headaches and back pain, reports the Argus Leader.

Gallagher and Wendt are scheduled to make their first court appearance on Tuesday. They are being held on $25,000 bond.