Prosecutors in the United States on Thursday added four new charges of racketeering, wire fraud, money laundering and obstruction of justice to the eight fraud charges Conrad Black already faces.

The new charges were contained in an indictment returned by a grand jury in Chicago and announced by U.S. District Attorney Patrick Fitzgerald.

"These latest allegations add nothing new to the indictment and, when we are given the opportunity, they will be demonstrated to be unfounded as well," Black's lawyer Edward Greenspan said in a statement issued Thursday.

Conrad Black leaves a Chicago court on Dec. 1 after his arraignment on fraud charges. (CP file photo)

Black is due to appear in court in Chicago at 9:30 a.m. local time for arraignment on the news charges.

The obstruction charge relates to an incident in May when Black and two employees were seen on videotape lugging boxes out the back door of the downtown Toronto office of Hollinger Inc., the company from which he once ruled his news empire.

After the security tape was played in a court in Ontario, Black agreed to return the boxes, which he said contained only personal items.

• FROM MAY 26, 2005: Caught on tape: Black to return boxes taken from Hollinger

The racketeering count, brought under the Racketeer Influenced and Corrupt Organizations (RICO) Act, alleges that Black was the principal leader, manager and organizer of the group of the people and entities that made up the "Hollinger Enterprise."

The racketeering charge alleges that Black, together with other defendants, operated Hollinger between 1998 and 2002 "through a pattern of seven racketeering acts, each containing one or more underlying allegations of fraud."

The racketeering and obstruction charges each carry a maximum of 20 years in prison and a $250,000 US fine upon conviction.

The money laundering charges carries a maximum sentence of 10 years in prison and a fine of twice the amount of illegally transferred funds – $4.3 million US in this case. The wire fraud charge carries a maximum penalty of five years in prison and a $250,000 fine.

The U.S. Attorney's Office in Chicago charged Black on Nov. 17 with eight counts of mail fraud and wire fraud relating to the alleged diversion of millions of dollars from Hollinger International. He faces up to 40 years in prison if convicted on those charges.

Black pleaded not guilty Dec. 1 to the eight fraud charges.

• FROM DEC. 1, 2005: Conrad Black pleads not guilty

• FROM NOV. 17, 2005: Conrad Black charged with 8 counts of fraud

Black is to appear in a Chicago court Friday morning to face the new charges.

Black's co-accused, former Hollinger International executive Peter Atkinson, John Boultbee and Mark Kipnis, have all pleaded not guilty to fraud charges.

Thursday's indictments also included one new charge of wire fraud against Boultbee.