There were scenes of chaos in Newport last night, as drugs were spilled across a city street and a man was critically injured after getting knocked down by a van and possibly stabbed.

Six men were arrested over the course of the drama, which saw armed police officer descend on Bank Street, St Julians, while a 37-year-old man remains critically injured but stable in the University of Wales Hospital.

Bank Street was cordoned off with firearms officers rushing to the scene after police received numerous calls about erratic driving and a violent altercation involving a weapon.

Residents described hearing shouts and screeching tyres at around 5.50pm on Monday after two Audis pulled up in the street. The occupants of both cars got into a heated argument, with one witness describing seeing two men fighting over a dark coloured coat filled with drugs.

He said: “As they were fighting over the coat, the weed [cannabis] went all over the road. It came out in a plume. It was definitely cannabis, I went and had a look after they had driven off. I could smell it as well - it went everywhere. They were scooping it away in a hurry. There were two tussling over the coat and then [another] lad came from the car with a kitchen knife and I thought, “I ain’t staying out here!”

Police said they had found a “significant” amount of controlled drugs at the Bank Street scene, but said they couldn't confirm the exact substance until it had been tested by scientists. They also recovered a weapon, believed to be a BB Gun.

Witness reports suggested the two Audis had driven along the M4 together. The occupants were from outside the area. All were arrested, except the 37-year-old man who was critically injured. He had originally been in the white Audi, but was hit by a van while standing beside Caerleon Road.

Police are in contact with the hospital to find out when the injured man will be well enough to speak to and they are also investigating the possibility he had earlier been stabbed in the leg.

Another Bank Street resident described how his wife had witnessed the incident. He said: "There was a knife involved and a BB gun, shouting and swearing. This guy got out of a car who was covered in blood. Everyone just kind of sped off.”

Detective Superintendent Ian Roberts said: "We would like to reassure residents of Newport that this is an isolated incident and all of those arrested are from outside the area. Bank Street was cordoned off in order to conduct a search for evidence but it was apparent we were dealing with a complex and fast moving incident.”

There are about 20 officers currently working on the case.

Police asked anyone with information about the incidents to call Gwent Police on 101 and quote log number 428 26/8/13.

PANEL

- Four men from Cardiff pulled up on Bank Street in a white Audi. Two of the occupants, aged 26 and 20, were found with the vehicle in Highbank. A third occupant, a 20-year-old man, was found later. All were arrested on suspicion of dangerous driving, possession of an offensive weapon, assault and possession with intent to supply. The fourth man, 37, remains critically injured in hospital.

- Two men from Bristol drove up in a grey Audi. They were stopped close to Junction 22 of the M4 and the men, both aged 27, were arrested on the same charges.

- A van driver from Newport, 47, was arrested on suspicion of dangerous driving after he hit the 37-year-old pedestrian on Caerleon Road, believed to have been injured in the leg during the earlier Bank Street altercation. The van is not connected to the original incident.