Footage has emerged of a group of masked offenders allegedly attacking students outside a school in Melbourne’s north.

Greenvale Secondary College was plunged into lockdown after two students were injured in an alleged affray which began about 3.12pm today.

Police are investigating after five people allegedly approached students outside the school on Glencairn Drive.

A scuffle broke out and two students sustained minor injuries, police said.

Bystanders filmed the alleged attack, which showed punches being thrown between a group of people.

Police believe one person produced a machete at the scene but it was not used in the affray.

In an email to parents, the school’s principal said the college was put into lockdown but assured them students and staff are safe.

The five alleged offenders left the area in a car and have not been located.

Police have described it as a “targeted” incident.

Ambulances were called to the incident, however no emergency treatment or hospital transport was needed.

An investigation remains ongoing.