Members of the Pagans motorcycle gang plotted to use grenades in a murderous assault on the rival Hells Angels, federal officials said Wednesday in announcing a litany of charges against 19 reputed Pagans members and associates in five states.

Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives, assisted by local police, arrested the 19 during early morning raids in New York, New Jersey, Delaware, Maryland and Massachusetts, ATF special agent-in-charge Ronald Turk said.

Seven of the defendants were based on Long Island, where they were ordered held without bail at their arraignments in U.S. District Court. The charges included racketeering, murder conspiracy, assault, extortion, drug distribution, witness tampering and firearms offenses.

According to an indictment, several members of the Long Island chapter of the Pagans Motorcycle Club met with gang members from other chapters last Sunday in New Jersey, where they discussed killing members of the Hells Angels. ATF officials say the conspirators had drawn up a list of possible targets and were instructed to be prepared to die or go to prison in completing their mission.

The arrests interrupted the conspiracy before anyone was injured, Turk said.

The Pagans and Hells Angels have long been violent rivals. In 2002, Pagans members with bats and pipes crashed a Long Island motorcycle expo sponsored by the Hells Angels. One Pagans member was shot and killed during the confrontation, and at least 10 other people were injured.

Seventy-three Pagans, from as far away as Ohio, Maryland and Pennsylvania, were convicted of or pleaded guilty to federal charges in the case.

Turk said this was the largest roundup of Pagans members on Long Island since that 2002 case.

ATF officials said one of their agents had infiltrated the biker gang and provided inside information on what the plotters were up to. The undercover agent was so trusted that the Long Island chapter named him its sergeant-at-arms, a position of authority within the gang.

Turk called the Pagans "a major outlaw motorcycle gang with influence throughout the Northeast and other parts of the country." He said additional arrests were possible.

Authorities said that during the raids Wednesday they seized 34 firearms and one improvised explosive device.

Among those arrested was John Eberling, whom prosecutors identified as an official in the Pagans national governing body, known as the Mother Club.

Eberling intends to fight the charges, said his attorney, Glenn Obedin.

"I think the indictment overemphasizes my client's position" within the Pagans, Obedin said.