The accounting irregularities at WorldCom Inc. have ballooned to at least $7.1 billion -- nearly twice the amount originally disclosed, the company revealed Thursday in a statement acknowledging that more problems may be uncovered.

The bankrupt telecommunications giant, which owns No. 2 long distance carrier MCI Corp. and provides much of the equipment that runs the Internet, disclosed that it had found at least $3.3 billion more in accounting misstatements dating to 1999. Those irregularities are on top of the $3.8 billion in bogus recordkeeping uncovered in June.

The June revelation led to criminal fraud charges against two top former WorldCom officials who were arrested and handcuffed last week by federal authorities in New York. The new discoveries are certain to intensify the federal investigation into other company executives, including former Chief Executive Bernard Ebbers, who was forced out in April.

"We knew the problem was a lot bigger than WorldCom told us, but the extent of this fraud is staggering," said Ken Johnson, spokesman for Rep. W.J. "Billy" Tauzin, R-La., chairman of the House Energy and Commerce Committee, which is investigating WorldCom's failure. "It's hard to believe that Bernie Ebbers had no idea what was going on."

Like the earlier misstatements, the problems revealed Thursday appear to have been designed to boost the profitability picture at WorldCom, a Wall Street darling during the telecommunications run-up in the late 1990s. The company, based in Clinton, Miss., filed for Chapter 11 bankruptcy protection July 21. It was the largest such filing in U.S. history, with the company listing $107 billion in total assets and $41 billion in debts.

The new disclosure adds to the string of accounting scandals that has tarnished some of the nation's largest firms, felling once-mighty companies such as Enron Corp. and Global Crossing Ltd. The revelations have shaken investor confidence, pummeling stocks and prompting calls for corporate reform.

Experts said it is unclear just what the ramifications of the new accounting shell game could be for a company already in bankruptcy. But as the sum of the bad bookkeeping rises, the likelihood that WorldCom could successfully reorganize and emerge from bankruptcy diminishes.

If the new revelations indicate that fraud occurred much earlier than known, it could have an effect upon the order in which WorldCom's creditors line up for payment, said Ram Ramakrishnan, head of the accounting department at the University of Illinois at Chicago.

"These new revelations could make a difference in the bankruptcy proceedings," he said.

The company's ability to continue supplying its customers with telecommunications services also could come into question as the scope of WorldCom's financial problems expands.

On Thursday before the latest revelation, SBC Communications Inc. applied to the bankruptcy judge to get upfront payments for services that SBC provides WorldCom. Should other carriers follow suit, it could become extremely difficult for WorldCom to continue operating in the highly interconnected world of telecommunications.

SBC and several other telecom companies have seen their quarterly earnings drop as a result of their exposure to WorldCom debt since the bankruptcy filing.

Earlier this week Chicago-based Telephone and Data Systems Inc. had to restate its second-quarter earnings in light of WorldCom's bankruptcy.

The fraudulent accounting already revealed occurred in 2001 and the first half of 2002. As a result of the new findings, WorldCom said it will restate its financial reports for all of 2000 and will likely write off $50.6 billion in goodwill and other intangible assets to reflect the reduced value of acquisitions it has made.

Company spokesman Brad Burns said the figures disclosed Thursday have been reported to the Securities and Exchange Commission and other investigative authorities.

WorldCom said the earlier misallocation of operating expenses as capital investments enabled the company to claim a profit when it actually suffered losses. The new disclosures appear to be a mix of similar irregularities, along with an improper classification of money set aside in so-called reserve accounts.

The company said its internal financial review is not yet complete, and that "additional amounts of improperly reported [earnings] and pretax income may be discovered and announced."

Ramakrishnan said that the company's new auditor, KPMG, is working to find everything missed by Chicago-based Andersen, the auditor that had signed off on the financial statements now found to be faulty.

After revealing the original accounting troubles in June, WorldCom fired Scott Sullivan, its chief financial officer, and accepted the resignation of David Myers, the company's controller. Last week both were arrested and charged.

The investigation is continuing, and Ebbers, the former CEO, is an obvious target. Ebbers owes WorldCom nearly $400 million that he borrowed while running the company.