By Tom Hals

WILMINGTON, Delaware (Reuters) - Tribune Co's plan to end its 20-month bankruptcy appeared to unravel on Friday with threats that the parties must accept a new plan or face legal fights, while creditors warned they might try to seize control of the reorganization.

The owner the Los Angeles Times, Chicago Tribune and more than 20 television stations told a court that talks about how to repay creditors, which continued past the hearing's scheduled start, had failed.

As a result, the company will file a new plan without input from creditors on August 27.

"We have tried mightily to bring the parties together. That has not happened," said Tribune's attorney, James Conlan of Sidley Austin.

Tribune filed for bankruptcy in December 2008, less than a year after real estate developer Sam Zell led a leveraged buyout of the media company.

Bondholders have claimed the buyout amounted to a "fraudulent transfer" that piled the company with unsustainable new debt and potentially wiped out their investment. They have threatened a legal fight to remove the buyout lenders, including JPMorgan Chase & Co, from the front of the line for repayment.

Tribune had a plan earlier this year to settle those legal issues, but that was undone by an examiner's report last month which emboldened bondholders, who are near the back of the line for a payout.

Conlan told Delaware's bankruptcy court that weighing the examiner's report and the company's performance "brings us to the place where we're well qualified to say who's been unreasonable and who's overestimating their leverage and who's not."

Conlan said the amended plan would be designed to win the support of all creditors, but failing that "we'll need to initiate litigation relating to fraudulent transfer issues."

The company's plans seemed to take creditors by surprise. A lawyer for the committee of unsecured creditors in the case said he was unaware of the plans until he arrived at court.

Many of the attorneys only offered brief comments on the news and said they wanted to see Tribune's plan.

This much was certain: a new plan would delay the company's emergence from bankruptcy. Prior to the examiner's report, the company was planning on having court approval of its reorganization by the end of this month.

On Friday, Conlan said Tribune would ask the court to set aside time in November to approve the new plan, although some creditors said even that might be rushing things.

The attorney for unsecured creditors noted that Tribune no longer has the exclusive right to propose a plan and control the bankruptcy.

"Parties of interest have options," said Howard Seife, a Chadbourne & Parke attorney who represents the creditors committee. "Other parties could file plans."

An attorney for JPMorgan said there could be several creditor groups offering up their plans.

The case is In Re Tribune Co, U.S. Bankruptcy Court, District of Delaware, No. 08-13141.

(Reporting by Tom Hals. Editing by Robert MacMillan)