UPDATED 7.46PM: There are claims tonight that up to a hundred people gathered outside a South Auckland KFC outlet tonight before a massive brawl broke out inside.

About 30 students burst into the store on Massey Road in Mangere East around five o'clock and used knives, threw chairs and pieces of wood at one another.

Terrified staff locked themselves inside businesses on Massey Road in Mangere, and others watched as students received injuries bad enough to draw blood.

A KFC employee said the girls and boys appeared to be under 16, some were bleeding, and some were covering their faces with their hands.

Another witness said the fight was terrible, and appeared to be a dispute between groups from two different schools.

Staff at a nearby library say they could see a weapon amongst the group.

They immediately locked the doors of the library to protect customers.

Four people were arrested., including two adults and two young people.

A large number of police officers converged on the area, and students were seen being taken away in police cars.