Police in Vancouver, Wash., arrested an 11-year-old boy on suspicion of attempted murder after finding a handgun, 400 rounds of ammunition and knives at his school, reports said.

The Columbian and CNN reported that the boy, who has not been named but is a student at Frontier Middle School, forced the school to be put into lockdown on Wednesday for about two hours.

There were no reports of injuries and it was not clear who the alleged targets were.

Parents weren't notified of the incident until students brought a note home, The Columbian reported.

The arrest follows a Nevada middle school shooting earlier this week in which the adolescent gunman killed himself and a teacher. A 14-year-old in Boston was also arrested this week after police found a teacher dead near the young teen's school.