US oil giant Chevron says it will appeal against an $8.6bn (£5.3bn) fine imposed by Ecuador judges, carrying on a long-running row over pollution.
Chevron's Kent Robertson told the BBC the case was an "extortion scheme", and accused Ecuador's state-run firm of polluting the country's Amazon region.
The legal wrangle has been going on for almost two decades, and has spawned lawsuits in the US and Ecuador.
Analysts say further appeals are likely to drag on for years.
The oil firm Texaco, which merged with Chevron in 2001, is accused of dumping billions of gallons of toxic waste into unlined pits and Amazon rivers between 1972 and 1992.
Campaigners say crops were damaged and farm animals killed, and that local cancer rates increased.
'Triumph of justice'
But Chevron says Texaco spent $40m cleaning up the area during the 1990s, and signed an agreement with Ecuador in 1998 absolving it of any further responsibility.
Mr Robertson, the firm's spokesman, told the BBC's World Today programme that Texaco had "operated admirably" and blamed Ecuador's state-run firm Petroecuador for any ongoing problems.
"The oilfields in question have been solely operated by the government of Ecuador's own oil company Petroecuador for the last 20 years," he said.
"Petroecuador has a deplorable environmental record and Chevron is getting blamed for actions in a country that we've never even operated in."
He accused Petroecuador and Ecuador's government of failing to live up to their responsibilities. Neither have responded to the claims.
The lawsuit was brought on behalf of 30,000 Ecuadoreans, and their lawyer Pablo Fajardo described the court ruling as "a triumph of justice over Chevron's crime and economic power".
But he said the damages were not enough, and pledged to appeal.
Environmentalists hoped the case would set a precedent, forcing companies operating in developing countries to comply with the same anti-pollution standards as in the industrialised world.
US-based lobby groups Amazon Watch and Rainforest Action Network said in a joint statement that the decision was "historic and unprecedented".
"Chevron has spent the last 18 years waging unprecedented public relations and lobbying campaigns to avoid cleaning up the environmental and public health catastrophe it left in the Amazon rainforest," the groups said.
But analysts say Chevron is determined that it will not pay the fine.
Earlier this month, the firm took its case to the Permanent Court of Arbitration in The Hague, which ordered Ecuador to suspend enforcement of any judgement against Chevron to allow arbitration to continue.
Separately, Chevron has also filed a case in the US courts accusing the claimants and lawyers in the case of racketeering, tampering with witnesses and obstructing justice.