The court agreed that firms had systematically lied about health risks
A US appeals court has largely upheld a landmark ruling that cigarette makers lied about the health risks of smoking.
Washington's Court of Appeals rejected an appeal by tobacco firms against a 2006 decision that banned labels such as "low tar" and "light".
Companies including Philip Morris USA were found guilty of racketeering and fraud over the issue.
Judges upheld the previous ruling, but excluded one firm and two trade groups from their judgement.
They ruled that the trade bodies - Council for Tobacco Research-USA and Tobacco Institute - had not made or sold products, so could be excluded.
And the firm Liggett was excused because it had co-operated with the authorities and acknowledged health risks.
But the judges rejected an argument from the other tobacco firms that they had never claimed that "light" cigarettes were less harmful.
"Defendants knew of their falsity at the time and made the statements with the intent to deceive," Friday's ruling said.
The 2006 ruling said firms had set up a "gentlemen's agreement" not to compete over whose cigarettes were the least damaging to health.
Lawyers for the tobacco companies denied that they had conspired to avoid public discussion of health risks.
The original ruling also required firms to issue "corrective statements" about health effects and addiction.
It has not been applied while the case has been under appeal.
Murray Garnick, lawyer for tobacco firm Altria - the parent company of Philip Morris - said the court's ruling was "not supported by the law or the evidence presented at trial".
"We believe the exceptional importance of these issues justifies further review," he said.
Other companies that were contesting the 2006 ruling included British American Tobacco, Lorillard Tobacco, RJ Reynolds Tobacco, and Brown & Williamson Tobacco.
The companies are now likely to take their appeal before the US Supreme Court, although commentators say that their chances of success are slim.
In a decision last December on an unrelated case, the Supreme Court ruled that smokers can sue tobacco firms over the misleading marketing of "light" or "low tar" cigarettes.