Six youths are in police custody after a lockdown at a high school in Milton, Ont.

Halton regional police Const. Ryan Anderson says officers were called to the Bishop Reding Catholic Secondary School at around 11:30 a.m. after receiving reports that a group of people was chasing another group while waving a firearm.

Anderson says police followed the group off school grounds, but ultimately arrested seven people on school property.

One of the teens has been released, while the others remain in custody.

Anderson says no one was injured, but police have recovered a knife and two other weapons believed to be either real or replica firearms.

The Halton Catholic District School Board issued a tweet saying a lockdown that was in place at the school has been lifted, but students have been sent home early while police continue their investigation.