Fight breaks out in McDonald's car park leaving one victim with stab wounds

There has been a brawl south of Perth, that has left three people injured, including one with multiple stab wounds.

Police say a fight between a group of men broke out in a McDonald's car park in Baldivis.

It all started at about 10.30pm on Monday and resulted in three people being taken to three different hospitals, a police spokesperson said.

Officers inside a McDonald's restaurant following an alleged stabbing. Source: 7 News

Authorities are still trying to determine exactly how the altercation unfolded.

One witness told 7 News he was with three other friends, aged between 16 and 18, who claimed they saw two people break a car windscreen with a brick in the car park.

The witness claimed they approached the two men, who then allegedly pulled a knife on them.

Police responded to reports of an altercation on Monday night. Source: 7 News

They told 7 News they were chased before the altercation continued on the street.

One teenager remains in hospital in a critical condition.