The United States has become the 108th country to sign the World Health Organization's global treaty on tobacco control, a decision hailed by some anti-tobacco advocates but viewed with skepticism by others who doubt the Bush administration will push for ratification.

The treaty was signed Monday night by Health and Human Services Secretary Tommy G. Thompson, who called it an important step toward reducing tobacco use.

"The United States has long been a world leader in anti-smoking efforts," Thompson said in a statement. "We have committed more resources than any other country to the research, development and evaluation of smoking control and cessation programs, both at home and abroad. President Bush and I look forward to working with WHO and other member nations to implement this agreement."

According to HHS spokesman Bill Pierce, no schedule has been set for submitting the treaty to the Senate for ratification.

The treaty provides a set of principles and a framework for action on issues ranging from tobacco advertising to excise taxes and cigarette smuggling.

Signing the treaty does not commit the United States to any changes in its tobacco policies, although it does require the government not to undermine the agreement. Even ratifying the treaty would not significantly change how tobacco is regulated in this country, unless Congress passes the legislation the treaty recommends or requires.

The U.S. delegation to the treaty negotiations came under sharp criticism here and abroad amid perceptions that the United States, under the influence of tobacco companies, was trying to weaken the agreement.

Yesterday, however, Mark Berlind, a vice president at Altria Group Inc., formerly called the Philip Morris Inc., said his company supported the treaty and wants it ratified. He said the treaty calls for many of the changes and regulations that his company has been seeking under legislation to give the Food and Drug Administration authority to regulate tobacco.

But R.J. Reynolds Tobacco Co. spokesman Seth Moskowitz said the United States already has enough tobacco regulation and that the treaty should not be ratified. "We don't think it's necessary," he said. "The government already has ample authority to regulate the industry."

The American Medical Association praised the decision, saying, "Tobacco now kills some 5 million people each year. Without this new international treaty, that number could climb to 10 millions deaths a year. . . ."

WHO is scheduled to flesh out and implement the tobacco framework at a meeting in New York next month, the first major gathering since the organization approved the agreement one year ago. Some observers said the Bush administration signed the treaty now to make sure it could participate in that meeting.

"What will be critical to watch is whether the U.S. contributes constructively to those negotiations," said Matthew Myers, president of the Campaign for Tobacco-Free Kids. "The U.S. participation leading up to the framework convention was deeply disappointing . . . often the voice for watering down or weakening the treaty."

He said that U.S. support of the treaty could be important if it leads to additional momentum toward granting the FDA regulatory power over tobacco.

The tobacco control and corporate responsibility group Infact said yesterday that it did not hold out much hope for the treaty in the short term.

"Unfortunately, our government has a history of signing treaties, leveraging its power to weaken the treaties, and then never ratifying them," Infact executive director Kathryn Mulvey said. "This is a stunning PR maneuver. We are not holding our breath for the U.S. to ratify the treaty."

The treaty will take effect once 40 governments have ratified it; so far nine have, and the European Parliament has recommended ratification.

The agreement would have its greatest impact in less developed nations where smoking is not widespread.

Signatories are required to ban cigarette advertising -- unless their constitutions forbid such a step -- and are encouraged to increase tobacco taxes. The treaty also requires cigarette makers to increase the size of health warnings so they take up at least 30 percent of the package cover.