The U.S. Securities and Exchange Commission has filed fraud charges against Canadian-born Conrad Black, the former chairman and CEO of Hollinger International, accusing him of "cheating and defrauding shareholders."

Also charged is David Radler, Hollinger's former president and chief operating officer.

The civil lawsuit alleges Black and Radler "engaged in a fraudulent and deceptive scheme to divert cash and assets" from the newspaper operating company between 1999 and 2003,  which they then hid from investors.

"Black and Radler abused their control of a public company and treated it as their personal piggy bank," Stephen Cutler, the SEC's director of enforcement, said in a statement Monday.

"Instead of carrying out their responsibilities to protect the interest of public shareholders, the defendants cheated and defrauded these shareholders through a series of deceptive schemes and misstatements."

The charges follow a year of SEC investigations into payments made to Hollinger executives.

The SEC alleges Black, Radler and Hollinger Inc. -- Hollinger's Toronto-based holding firm -- diverted $85 million US to themselves, other corporate insiders and Hollinger Inc., using proceeds from Hollinger International's sale of newspapers through "non-competition" payments.

They also allegedly orchestrated the sale of some Hollinger International's publications at below-market prices to another privately-held company owned and controlled by Black and Radler, including the sale of one publication for $1.

They then misled Hollinger International's Audit Committee and Board of Directors about the  transactions, the SEC alleges.

The allegations have yet to be proven in court.

Black and Radler have said they will fight the allegations and expect to be vindicated.

If the allegations are proven, they could lead to regulatory sanctions. Those sanctions could see Black fined, asked to pay back the allegedly "ill-gotten gains," and even barred from being a director of any public company.

The U.S. Department of Justice is also investigating Black and may choose to lay criminal charges.

Black resigned as Hollinger International's chairman last year. The company quickly sued, accusing Black and other former executives of "looting'' millions of dollars from the company.

The company ousted Black as CEO last year, later removing him as chairman over disputed payments he collected from the company. It recently amended the suit against Black and the others, raising the claim to $542 million US from $400 million.

Black has denied helping himself to the company's money, but has acknowledged errors in financial reporting.

Black has also fought back. He has filed suit in Ontario against Hollinger International's independent directors and their adviser, former SEC chairman Richard Breeden, demanding $850 million for alleged defamation, conspiracy to injure, interference with economic relations, intimidation and misrepresentation.

Black, meanwhile, has resigned as chairman and chief executive of Hollinger Inc., the holding firm that has voting control over Hollinger International. Black has announced his intention to buy out the minority investors and take Hollinger Inc. private.

Hollinger International recently sold the London Telegraph group, but still owns the Chicago Sun-Times, the Jerusalem Post and other media assets.