Communications between Berkshire Hathaway Inc Chairman Warren Buffett and former American International Group Inc Chairman Maurice Hank Greenberg won't have to be turned over to the former head of a Berkshire unit whose fraud trial begins Monday.

A lawyer for Ronald Ferguson, the former chief executive of Berkshire's General Re Corp reinsurance unit, withdrew his request for communications from 2000 to the present, according to a Friday court filing by Gregory Weingart, a lawyer for Berkshire and Gen Re.

The lawyer for Ferguson also withdrew a request for communications between Ferguson and current Gen Re chief Joseph Brandon that mention Buffett, Weingart's filing shows. Ferguson may renew his request as the trial proceeds, the filing shows.

Berkshire and Gen Re continue to oppose Ferguson's subpoena for interim reports that Ferguson sent Buffett from January 1998 to September 2001, a separate filing shows. Weingart called the demand a fishing expedition, in part because it covers a period 2-1/2 years before any alleged fraud.

Prosecutors have accused Ferguson and four others of fraud, conspiracy and making false statements in connection with a 2000 transaction they say allowed AIG, the world's largest insurer, to fraudulently inflate reserves by $500 million in 2000 and 2001.

Other defendants are former Gen Re Chief Financial Officer Elizabeth Monrad, former Gen Re senior vice president Christopher Garand, former Gen Re assistant general counsel Robert Graham and former AIG head of reinsurance Christian Milton.

The defendants are being tried in federal district court in Hartford, Connecticut. On Wednesday, U.S. District Judge Christopher Droney rejected a subpoena from Ferguson demanding that Gen Re turn over documents in 2000 among Buffett, Brandon and Franklin Tad Montross, now the reinsurer's president.

Berkshire has said Buffett was not briefed on the structure of the AIG transaction and was unaware that it might have any improper purpose. Prosecutors have said they do not plan to require Buffett to testify without evidence from the defendants that he was involved in or approved the transaction.

Greenberg has also denied wrongdoing. He built AIG over nearly four decades before being ousted in March 2005.

(Reporting by Jonathan Stempel; Editing by Gerald E. McCormick)