Authorities thwart school shooting in Los Angeles -- and seized assault-style rifle with 100 rounds of ammunition

Authorities have thwarted another mass shooting. A 13-year-old boy was planning a mass shooting at his Los Angeles school but police were able to stop him and seize his weapons.

Among the items taken was an assault-style rifle with about 100 rounds of ammunition, according to CNN's Josh Campbell.

According to NBC News, "the discovery was made in response to a call about a student who wanted to shoot other students and staff. He added that the suspect, who was not immediately identified, purchased parts on the internet to build a "ghost gun" — meaning it was assembled at home and had no serial numbers, a way for owners to avoid registering them."

"We moved quickly to ensure that no harm came to our students," the school district said. "Our students did everything right by raising concerns with adults."