There's been a long-standing feud between the two motorcycle gangs

Herbert Faust, Nassau police

At least 10 others were injured, two critically, and about 70 people were taken into custody, police said. Police and federal agents at the scene seized hundreds of weapons, including knives, baseball bats, handguns, shotguns and an Uzi machine gun.

The clash was just the latest violence in a long-running feud between the Hell's Angels and the Pagans gang, Nassau County Chief of Detectives Herbert Faust said.

Mass rioting

Raymond G Dwyer, 38, from Oceanside, New York, was charged with second-degree murder in the shooting of Robert Rutherford, a suspected member of the Pagan gang.

The charge carries a maximum sentence of 25 years to life.

The event included a tattoo competition

Lieutenant Frank Guidice, commanding officer of the Nassau County homicide squad, said Mr Dwyer fired five or six shots from a pistol, hitting Rutherford, aged 51, in the chest. He died later during surgery.

Police have charged 73 people with rioting in the first degree, attempted gang assault in the first degree and weapons charges, Mr Faust said.

With the exception of Mr Dwyer they have all been identified by police as members of the Pagans, Mr Guidice said.

Gang invasion

About 1,000 members of the Hell's Angels motorbike club were at the event, sponsored by its Long Island chapter, when 100 rival Pagans arrived in a fleet of 10 vans.

The Pagans rushed in the front door and began overturning tables and smashing property and a wild brawl ensued, according to police.

"There's been a long-standing feud between the two motorcycle gangs," Mr Faust said.

"We had surveillance. We were aware of the event. We had no reason to believe it would have erupted into this type of conflict," he added.

The second day of the scheduled two-day exposition was cancelled on Sunday.