Ecuador's Supreme Court agreed Thursday to hear an appeal by US oil giant Chevron to overturn its 2011 judgment and record fine for environmental damage.

Chevron's 280,000 pages of documents from litigation that started in 1993 were filed with the National Court of Justice in Quito, AFP has learned.

A lower court ordered Chevron to pay an $9.5 billion fine after years of unchecked pollution in the Amazon attributed to Texaco, which Chevron acquired in 2001.

A court in Ecuador's Sucumbios Province upheld the judgment in January. But Chevron, which disputes the scientific evidence that led to the judgment, argues the conviction was improperly based on a retroactive law.

Chevron's court filings were transported by bus from the Amazon region to the capital under heavy escort at the company's request.

The Supreme Court's associate judges must ratify the admissibility of the appeal before it reaches a hearing for "a final resolution," Pablo Fajardo, an attorney for the plaintiffs, told AFP.

No date has been set for a hearing.

Chevron responded with a statement sent to AFP saying now "the Ecuadorian courts have a new opportunity to rectify the travesty of justice committed by lower courts."

James Craig, Chevron's spokesman in Latin America, added: "We also hope that the court is not swayed by the pressures of the plaintiffs' lawyers and the media circus that they themselves have created as a means to pressure the judges."

In February, an international arbitration panel recommended that Chevron's conviction and fine be suspended, but Ecuador's courts have refused so far.

The fine -- $8.64 billion plus a 10 percent fine -- is the highest ever against an oil company for environmental damage, far surpassing the $4.5 billion against ExxonMobil for the 1989 Prince William Sound spill in Alaska.

The plaintiffs from among Ecuador's indigenous Amazon communities say the environmental damage caused by Texaco included dumping waste oil into open pits between 1964 and 1990, which then contaminated soil and rivers.