HARRISBURG — Intimidation, assaults and property damage, including setting a crane on fire, were part of an alleged campaign by a Philadelphia-area ironworkers union to coerce building contractors into hiring them over non-union competition, federal prosecutors said today as they arrested 10 of the union's agents and members.

The federal charges against the men include racketeering and arson, and targeted properties included a Toys R Us store in suburban Philadelphia and a Quaker meetinghouse in the tony Chestnut Hill section of Philadelphia, U.S. Attorney Zane David Memeger said. The indictment's allegations appear to back up longstanding complaints by businessmen over union tactics in Philadelphia.

In a 49-page grand jury indictment, prosecutors say the defendants helped create “goon” squads to carry out the assaults and property destruction against non-union contractors in an attempt to force them to hire Ironworkers Local 401's members.

One goon squad referred to itself as T.H.U.Gs, short for The Helpful Union Guys.

The indictment documented 11 episodes over three-plus years through October 2013. In a statement, Philadelphia's FBI special agent-in-charge, Edward J. Hanko, called the union's tactics “outrageous and brazen” and said he expected more victims to come forward.

In a statement, Walter W. Wise, president of the Ironworkers international union, said “we have never and will never tolerate any of the alleged acts contained in the accusations.”