Attorneys for former President Donald Trump filed a motion on Wednesday requesting a mistrial in his New York civil business fraud case, alleging that the judge in the trial is biased against him.

"The evidence of apparent and actual bias is tangible and overwhelming," the 30-page filing reads. "Such evidence, coupled with an unprecedented departure from standard judicial procedure, has tainted these proceedings and a mistrial is warranted."

The $250 million civil fraud case could have major implications for the former president's real estate empire and personal wealth. The case, brought by New York Attorney General Letitia James, accuses Trump, his adult sons Donald Trump Jr. and Eric Trump, and other top Trump Organization executives of exaggerating his wealth by billions of dollars on the financial statements by inflating property values. 

The documents were given to banks, insurers and others to secure loans and make deals. James is seeking millions in what she says were ill-gotten gains, and she wants the defendants banned from doing business in New York.

Before the trial, Judge Arthur Engoron ruled that Trump and other defendants committed fraud by exaggerating his net worth and the value of assets on his financial statements. The judge imposed a punishment that could strip Trump of some marquee properties, though an appeals court is keeping them in his control for now.

Trump has denied any wrongdoing and decried the case as a witch hunt at every turn. 

In Wednesday's filing, defense attorneys accuse Engoron and his principal law clerk of engaging in conduct that has "tainted these proceedings." 

"Only the grant of a mistrial can salvage what is left of the rule of law," the filing reads.

Engoron imposed a gag order on Trump after the former president repeatedly attacked his law clerk in posts online and outside the court room. Trump has already been fined twice for violating that order, resulting in $15,000 worth of fines. 

A spokesperson for the attorney general's office accused Trump of "trying to dismiss the truth and the facts, but the numbers and evidence don’t lie."

"Donald Trump is now being held accountable for the years of fraud he committed and the incredible ways he lied to enrich himself and his family," the spokesperson said in a statement to CNN. He can keep trying to distract from his fraud, but the truth always comes out." 

The Associated Press contributed to this report.