The U.S. government defended in federal court on Wednesday the requirement it has imposed on tobacco companies to place graphic images on cigarette packages warning about the risks of smoking.

In the hearing, tobacco companies asked a federal judge to block the requirement taking effect in September 2012, arguing that it violates the right of free speech stipulated in the Constitution.

"Never before has the government required the maker of a lawful product to tell consumers not to buy it," said Noel Francisco, a lawyer arguing on behalf of R.J. Reynolds Tobacco Co, Reuters reported.

The Tobacco industry sued the U.S. Food and Drug Administration because it doesn't want the graphic images to be shown on their products.

The nine images are very shocking, according to the industry. They include images of decayed teeth and a disease on the lip of a smoker, a pair of lungs tainted with green and brown marks next to a pair of healthy ones, and a cloud of smoke above a baby, among others.

The tobacco industry claims the new graphic warnings force it to "engage in anti-smoking advocacy" on the government's behalf, Reuters reported.

"The government can tell people how to live, but they can't force people who sell tobacco to be their mouthpieces," said Floyd Abrams, a lawyer representing the tobacco industry.

The federal judge questioned FDA lawyers in court yesterday on whether the requirement to place the graphic images is merely informative or if it goes beyond that as anti-smoking advocacy.

The government's lawyers said the images coupled with written warnings are designed to communicate the dangers to the public, reports the Associated Press.

"The advocacy here is to convey the negative health consequences of smoking. That's what Congress directed the FDA to do," said Mark Stern, a Justice Department attorney, according to the report from Reuters.

"The Constitution doesn't limit Congress to conveying information in a text-only format," he added fighting back claims from the cigarette companies that the images were chosen for their "shocking value" and not because they informed consumers better about the risks.

The labels are part of a 2009 law passed by Congress. In June, the FDA approved nine labels that companies are to print on the entire top half of cigarette packages, front and back. The new warnings must constitute 20 percent of cigarette advertising.