ATLANTIC CITY — The owner of the struggling Trump Taj Mahal Casino Resort filed court papers on Friday saying it would close next month, making it the fifth of this city’s 12 casinos to shut down this year.

In filing a revised reorganization plan in Delaware bankruptcy court, Trump Entertainment Resorts said its board had approved a shutdown of the casino by Dec. 12. It had threatened to close by then if its main union did not drop its appeal of a court-ordered cost-savings package.

The company said it would close because it had not received the state and local tax breaks it had sought in a bid to keep the Taj Mahal open.

“The debtors have initiated appropriate steps to cease operations at the Taj Mahal consistent with that time frame,” Trump Entertainment lawyers wrote.

Company officials declined to comment on Friday afternoon.

With the union appealing a bankruptcy court’s order terminating its collective bargaining agreement and the company’s pension funding obligations and New Jersey officials refusing to grant tax concessions, the Taj Mahal’s 3,000 workers will soon join some 8,000 other Atlantic City casino workers who have lost their jobs this year.

Mayor Don Guardian said he knew this was a difficult time for all the people who would be out of work. “I want them to know that the city of Atlantic City did everything they could to help keep the Trump Taj Mahal open,” he said. He added, however, that the company and its officials “still must pay their fair share of taxes, just like our residents do.”