New research from Harvard University's School of Public Health and the non-profit Legacy Foundation found that graphic warnings on cigarette packets may help smokers who are trying to quit.
A federal judge blocked a US rule that would have required tobacco companies to display graphic images such as a man exhaling smoke through a hole in his throat.
The judge granted tobacco companies a temporary injunction, saying they would likely prevail in their lawsuit challenging the requirement with a claim it is in violation of the First Amendment which protects free speech.
The Food and Drug Administration released nine new warnings that were to go into effect last September. A number of tobacco companies sued the FDA in August arguing that the new warnings would force them to "engage in anti-smoking advocacy" on the government's behalf.
A spokesman for R J Reynolds Tobacco Co said the company does not as a matter of policy comment on ongoing litigation.
What the study found
The new study, published in the scientific journal PLOS ONE, examined reactions to cigarette warning labels from more than 3 300 smokers who either looked at text warnings alone or at graphic images.
The study found that smokers who looked at the graphic images were 30% more likely to say they would quit within the next month than those who looked at the text warnings.
The findings were consistent across groups regardless of race, education or income.
The study was conducted by Harvard in conjunction with the Legacy Foundation, a non-profit organisation dedicated to encouraging people to give up tobacco.
Tobacco is the leading cause of preventable death in the United States, accounting for one in every five deaths, according to the Centers for Disease Control and Prevention. About 21% of US adults smoke cigarettes.
