Six youths who were arrested after a lockdown at a Milton, Ont., high school have now been charged with robbery and a weapons offence.

The six, who cannot be identified because they are underage, were taken into custody Thursday after an incident at Bishop Reding Catholic Secondary School.

Police have said they received reports that a group of people was chasing another youth while waving a firearm.

They said officers followed the group off school grounds, but ultimately arrested seven people on school property. One of them was released shortly afterwards.

Police said no one was injured, but officers seized a knife and a pellet gun.