Deposed AIG Chairman and CEO Maurice Greenberg has invoked his Fifth Amendment right to silence before being questioned by regulators over financial reinsurance deals with General Re.

Overnight reports from New York say Mr Greenberg made the decision to remain silent after Attorney-General Eliot Spitzer refused requests to delay an interview due today.

Mr Greenberg’s lawyers say they have not been given access to relevant documents. In a statement released yesterday, Mr Greenberg said he is “familiar with many, but certainly not all, or even a significant percentage of, the literally millions of transactions each year in approximately 130 countries” undertaken by AIG.

Meanwhile, Berkshire Hathaway CEO Warren Buffett, whose subsidiary General Re provided the financial reinsurance packages with alleged side letters that removed any element of risk, has been interviewed by investigators from Mr Spitzer’s office as well as the US Securities and Exchange Commission and the Department of Justice.

In interviews conducted overnight Australian time, Mr Buffett is understood to have said he knew few details about the transaction. In a television interview at the weekend, Mr Spitzer made it clear that Mr Buffett isn’t a target of the AIG investigation.

“The focus is AIG and Mr Greenberg, not Warren Buffett,” he said, adding that more than $1 billion of accounting fraud has been acknowledged by AIG.

“That company was a black box, run with an iron fist by a CEO who did not tell the public the truth.”