An 11-year-old US student appeared in court Thursday on suspicion of attempted murder after bringing a handgun and 400 rounds of ammunition into school, a spokesman said.
In the latest in a spate of incidents in US schools which have left four dead this week, the boy also allegedly brought "multiple" knives to the Frontier Middle School in Vancouver, in Washington state on Wednesday.
"The school was placed into lockdown for approximately two hours while officers were at the campus. There were no injuries related to this incident," said a statement released by local police.
"An 11-year-old male was interviewed by detectives and subsequently arrested for one count of attempted murder," it added.
A spokeswoman, Kim Kapp, told AFP that the boy made a first appearance Thursday morning in Clark County juvenile court.
The incident came after three fatal incidents in US schools this week.
On Monday a 12-year-old shot dead at a teacher at Sparks Middle School in Nevada, and also injured two fellow students before killing himself.
On Tuesday, Californian police shot dead a 13-year-old boy who was carrying a pellet gun that looked like an assault rifle.
The child, identified as Andy Lopez and described in media reports as popular in his school, was walking down a street when sheriff's deputies saw him carrying what appeared to be a rifle.
They ordered him to drop it and "and at some point immediately thereafter, the deputies fired several rounds from their handguns at the subject striking him several times," said the Sonoma county sheriff's office.
Then on Wednesday a 24-year-old teacher was allegedly killed by a 14-year-old boy at Danvers High School in Massachusetts. Police found blood in a bathroom of the school before discovering her body in nearby woods.
The incidents have fueled America's perennial debate about gun control, re-ignited in traumatic fashion by last December's massacre at a school in Newtown, Connecticut, which killed 26 -- including 20 young children.
In the wake of these killings, President Barack Obama pledged to pursue "sensible" gun control, after little was done following other recent mass shootings in the states of Colorado and Arizona.
But the administration made no progress in Congress.
Until Newtown, America's most notorious school shooting was when students Eric Harris and Dylan Klebold attacked the Columbine High School in Colorado in April 1999, killing 13 and wounding 23 before turning their guns on themselves.
[Pistol/handgun/revolver with school books on Shutterstock]