A YOUNG MOM walked into South Philadelphia High School with her baby Thursday morning packing more than diapers and bottles in her bag — police say she also was packing heat.

It was one of two incidents Thursday in which guns were brought into Philly high schools.

Cops said the woman, Kelly Jones, 21, of 69th Street near Elmwood Avenue in Southwest Philadelphia, went to the school about 10:45 a.m. to sign up for an evening high-school-diploma program, accompanied by her aunt and infant.

When school police scanned her pink-and-white diaper bag as a routine security measure, they spotted a handgun inside, according to Capt. Laurence Nodiff of the South Detective Division.

The gun, a .40-caliber Smith & Wesson semiautomatic, was fully loaded, with eight rounds in the clip and one in the chamber, cops said. The serial number on the gun was obliterated.

Jones was arrested at the school, on Broad Street near Snyder Avenue, and faces charges including violation of the Uniform Firearms Act, carrying a weapon on school property and possessing a gun with obliterated serial numbers. Nodiff said Jones did not have a license to carry.

When asked why she had the gun in the diaper bag, police said, Jones told them she didn't know it was there.

"She is claiming that she was not aware that the loaded .40-caliber Smith & Wesson semiautomatic handgun was in the diaper bag," Nodiff said.

She also told cops she didn't know how or why the serial number was obliterated.

Jones has a prior record that includes assault charges, but police declined to elaborate on it. The infant was placed in Jones' aunt's care at the school, and Jones was taken to the South Detective Division to be processed.

"[School] police officers did their job and stopped the threat right at the front door," Nodiff said. "At no time were students or faculty members in danger."

Jones wasn't the only person who tried to enter a Philly school with a gun Thursday.

Less than two hours later, at Broad and Green streets, an enterprising young thug tried to get a gun into Benjamin Franklin High by hiding the weapon in his shoe.

The ninth-grader arrived late around 12:15 p.m., according to School District Spokesman Fernando Gallard.

Police found the weapon when it set off a metal detector. School police confiscated the unloaded handgun, and it was found to be inoperable, Gallard said.

School officials called Philadelphia police and detained the student until turning him over to them.

Students who bring guns into schools are referred for expulsion, Gallard said. It was unclear whether the student was charged.

Thursday night, School District Superintendent William R. Hite Jr. said he commended the work of the school police in stopping the guns from getting into schools in both cases.

"It's a sad commentary when we have to have these kinds of discussions about weapons in schools," Hite said.

"That's the unfortunate part," he said. "This is not unique to Philadelphia."