FDA changes course on graphic warning labels for cigarettes

(CNN) -- The Department of Justice has sent a letter to House Speaker John Boehner saying it will not ask the U.S. Supreme Court to review a federal appeals court ruling that blocked new graphic warnings on cigarette packages.

The government had until April 5 to appeal the ruling, which struck down the mandate, saying the requirements were a violation of free speech protections.

The U.S. Food and Drug Administration instead will "undertake research to support a new rule-making consistent with the Tobacco Control Act," the letter said, meaning the FDA will have to create new warning labels.

The FDA didn't immediately respond to CNN's request for comment.