Chevron Corp. on Wednesday urged Ecuador's authorities to investigate the conduct of plaintiffs' lawyers and a judge who handed down an $18 billion decision in an oil pollution case.

The oil company said in a statement that it submitted a letter to the country's prosecutor general alleging there was fraud and corruption in the case. In the letter, the company accused the plaintiffs' lawyers of working with Judge Nicolas Zambrano to draft the February judgment.

Karen Hinton, U.S. spokeswoman for the Ecuadoreans who won the judgment against the company, dismissed those accusations.

"The Ecuador trial court decision finding Chevron guilty is based on valid scientific evidence, much of it provided by Chevron's own experts and auditors," Hinton said in an emailed statement. She said the company's letter "is nothing more than a public relations stunt orchestrated by Chevron to distract attention from its $18 billion liability."

Chevron has previously alleged fraud in the lawsuit over pollution of the Amazon rain forest more than two decades ago by energy company Texaco. Chevron bought Texaco in 2001.

The plaintiffs have also accused Chevron of defrauding the Ecuadorean court to hide the scale of the oil contamination.

Attempts to reach Ecuadorean authorities on Wednesday were unsuccessful.