America's largest tobacco companies are accused of lying about the effects of smoking over a 50-year period as a government lawsuit gets under way.
Smoking was "devastating" for public health, it is claimed
The case "is about a 50-year pattern of misrepresentation, half-truths and lies", US Justice Department lawyer Frank Marine said in opening comments.
Among the accused are Altria Group and RJ Reynolds Tobacco.
The $280bn lawsuit - filed by the Clinton administration in 1999 - is expected to conclude in six months.
Prosecutors want the cigarette firms to surrender $280bn in profits accumulated over the past 50 years and impose tougher rules on marketing their products.
"The government's case against the tobacco industry is an important effort to prevent fraudulent activity and uphold corporate integrity," US Attorney General John Ashcroft said in a statement on Tuesday.
Lawyers for the cigarette companies are scheduled to make their response to US District Judge Gladys Kessler on Wednesday.
In its lawsuit, the government claims tobacco firms manipulated nicotine levels to increase addiction, targeted teenagers with multi-billion dollar advertising campaigns, lied about the dangers of smoking and ignored research to the contrary.
The government has provided extensive evidence to support our case
Peter Keisler, assistant attorney general
A 1953 meeting in New York attended by executives from the country's top five cigarette makers resulted in a "massive 50-year scheme to defraud the public", the lawsuit claims.
The defendants include Philip Morris US, Reynolds American Inc, Lorillard Tobacco, the Liggett Group and Brown and Williamson, a US subsidiary of British American Tobacco.
The firms, which deny any wrongdoing, have been indicted under legislation drawn up to counteract Mafia infiltration of business.
"The government has provided extensive evidence to support our case," said Peter Keisler, assistant attorney general in the US Justice Department's civil division.
"We look forward to presenting it."
William Ohlemeyer, lead counsel for Altria Group, parent company of Philip Morris US, said claims made by manufacturers over the period about the risks attached to smoking had been done so honestly.
"They may have been wrong and in some cases they might admit it but that isn't fraud," he said.
Ohlemeyer said the industry has already met many of the government's demands in a landmark $206bn settlement reached with 46 states in 1998.
This severely restricted how cigarettes could be marketed, while subjecting tobacco firms to tougher regulatory controls.
More than 300 witnesses are expected to be called during the course of the trial.
An appeal against the lawsuit is still pending, while some analysts believe a settlement may be reached in the aftermath of November's presidential election.
"It becomes politically feasible at that point, I think, to have a resolution by non-litigation means," one Wall Street analyst told Reuters.