By Stephen Gibbs
BBC News, Havana
Cuba - the home of the fine cigar - has brought in tough new regulations on tobacco smoking in public places.
Bars and restaurants are not sure how to enforce the new rules
It is now banned in most work places, cigarette machines are being removed and it will be illegal to sell tobacco products close to schools.
Almost half of all Cuban adults smoke, and tobacco and cigar exports are vital to the country's economy.
The inspiration for the ban is said to have come from President Fidel Castro, who has given up smoking cigars.
In the hours before this resolution came into effect, many Cubans appeared unaware of it.
The government has been relatively low-key in promoting what on paper are among the toughest anti-smoking regulations in the world.
In the capital Havana, managers of restaurants and bars said they intended to set up non-smoking areas, but they seemed unclear as to how they would enforce the rule.
Cuba says it wants to change the attitude of its population towards tobacco.
It will be battling a culture that goes back five centuries. Many Cubans start the habit in their early teens.
Tobacco and cigar exports generate more than $200m (£107m) a year. But every year some 6,000 Cubans die from smoking-related illnesses.
It is thought to be a attempt to increase the average life expectancy here that drove the Cuban government to act now.
President Castro - a one-time keen cigar smoker - gave up in the mid-1980s.