WASHINGTON (Reuters) – U.S. President-elect Barack Obama failed to give a straight answer when asked on a U.S. talkshow on Sunday whether he had managed to quit smoking.

In a country where cigarettes are responsible for one in five deaths and smoking costs tens of billions of dollars in health care, Obama has been under pressure to set an example by giving up his reported two-decade-old habit.

Appearing on NBC's "Meet the Press" program, interviewer Tom Brokaw told Obama he had ducked answering the question during an interview last month with ABC's Barbara Walters.

Noting that the White House was a no-smoking zone, Brokaw asked Obama, "Have you stopped smoking?"

"I have," Obama replied, smiling broadly. "What I said was that there are times where I have fallen off the wagon."

"Wait a minute," Brokaw interjected, "that means you haven't stopped."

"Fair enough," Obama said. "What I would say is that I have done a terrific job under the circumstances of making myself much healthier. You will not see any violations of these rules in the White House."

Obama was often observed on the presidential campaign trail chewing Nicorette gum, which helps ease the craving for nicotine. He has tried several times to quit.

The 47-year-old president-elect, who takes office on January 20, works out daily at the gym and sometimes plays basketball. His doctor said in May he was in excellent health, often jogged 3 miles a day and was fit to serve as U.S. president.

Website www.cigaraficionado.com says Gerald Ford, who served from 1974-77, was the last U.S. president to use tobacco on a regular basis. The White House no-smoking rule was imposed by former First Lady Hillary Clinton, now Obama's nominee for secretary of state.