Police in Ontario's Halton region say they arrested seven youths and recovered multiple weapons on Thursday afternoon amid lockdowns and security measures at three schools.

Bishop P.F. Reding Catholic Secondary School was placed under lockdown, while nearby Chris Hadfield Public School and St. Peter's Elementary School were placed under hold and secure procedures. All security measures have now been lifted.

Officers responded to a call for assistance at around 11:30 a.m. ET from a school in Milton, Ont., a suburban town northwest of Toronto located in Halton region.

The callers said they were being chased by a group of males with a gun behind Bishop P.F. Reding school.

Police officers later located and arrested seven youths inside the school. Police recovered one knife and two firearms. One of the guns was determined to be a replica, while the other is still being examined.

Police say students and staff at all three schools are safe and uninjured.

Halton police said seven youth are in custody, but haven't revealed information about any potential charges. (Andrew Collins/CBC)

The hold and secure procedures were put in place at the nearby schools as a precautionary measure, police said.

One of the seven arrested youths has been released, while the others remain in police custody.

Police did not reveal information about any potential charges.