Two girls ages 11 and 12 who attend Bartow Middle School were arrested Tuesday on charges that they planned to conduct a stabbing attack at the school, according to Bartow police.The attack would have targeted up to 15 students during school hours Tuesday, police said, and was averted when police said school staff found the girls hiding in a bathroom plotting the attack. The girls were found with items such as butcher knives and a pizza cutter, police said.A school resource officer learned of the plot after being called to the principal's office at about 1:30 p.m. Another student had alerted a teacher about the two girls.After the pair were arrested, police said they discovered days worth of text messages between the two detailing their plans. The two girls wanted to target smaller students, drink their victims’ blood and then commit suicide, police said.Both girls told officers they worshipped Satan, according to police."This is horrific," Bartow Police Chief Joe Hall said during a news conference. "If I had children in school I'd be half scared to death."The Tampa Bay Times is withholding the identity of the two girls because of their ages. Each faces several charges, including conspiracy to commit first-degree murder.