* Restrictions take effect under anti-tobacco law
* Doubts over enforcement in cigarette culture
* Forty percent of Russians smoke
* Putin wants population to increase
Tobacco restrictions came into force in Russia on Saturday which President Vladimir Putin hopes will create a healthier workforce and help reverse a population decline, but they face stiff opposition in a country where four in ten people smoke.
The measures, part of a law Putin signed in February, include a ban on smoking at schools and universities, museums, sports facilities, hospitals and on public transport - in many cases places where it is already prohibited.
A minimum price for cigarettes is expected to be set next January and the biggest challenge to Russia's cigarette culture will come in June 2014: a ban on smoking in cafes, restaurants and hotels, and on tobacco sales at street kiosks.
Nearly 40 percent of Russians smoke, compared with 27 percent in the United States and 30 percent in France, according to the World Health Organisation's latest figures.
The average Russian life expectancy is 69, against 79 in the United States and 82 in France, according to the World Bank.
There are doubts about enforcement, and widespread debate among Russians over the impact of the new law.
Adopting it was the right thing to do, said Moscow resident Alexander. "I plan to quit smoking and hope this will help."
But opponents say it will not work and infringes on the rights of smokers. "Our country is not ready for this law," said prominent legal expert Mikhail Barshchevsky, likening it to former Soviet leader Mikhail Gorbachev's unpopular effort to crack down on drinking under his "perestroika" reforms of the late 1980s.
"This is not a law about fighting smoking, it's a law on genocide against smokers."
He said fines ranging from 500 to 1500 roubles ($15-$50) could lead to bribe-taking by police.
The law is designed to gradually bring the country in line with an international tobacco control pact and wean its citizens off a habit that Prime Minister Dmitry Medvedev has said kills almost 400,000 Russians every year.
Russia's population fell to 142 million in 2011 from 149 million in 1991, the year the Soviet Union collapsed, and experts warn it will fall further.
Putin, who could seek another six-year term in 2018, wants the population to increase instead, and has urged Russians - particularly young people - to live healthier lives.
Restrictions that came into force on Saturday also included a ban on smoking within 15 metres (50 feet) of entrances to airports, subway, train and bus stations, and in the stairwells of apartment buildings, and a reduction in the number of places where tobacco can be sold.
"It's a big step in strengthening the position of our society about the absolute evil that is smoking, but ... I think less has been done than could have been," Russia's consumer protection agency chief, Gennady Onishchenko, said on Friday.
In an early sign that enforcement may be a challenge, police said that for the first few weeks at least, they will issue violators verbal warnings but not fines.
The reason, according to Ekho Moskvy radio, is not mercy toward smokers but a legal oversight - the administrative code has not yet been adjusted to conform with the anti-tobacco law.
"In some cases it is not clear how these measures will be implemented and enforced," said Alexander Lioutyi, corporate affairs director of British American Tobacco's Russian division.
"Who will monitor violations of the law, as the number of policemen in Russia remains the same?" he said.
He said it was too early to evaluate the effect on Russia's $20 billion a year cigarette market, about 90 percent of which is controlled by foreign firms such as BAT, Imperial Tobacco , Japan Tobacco and Philip Morris.
On the streets of Moscow, pack-a-day smoker Igor Kolesnichenko, 40, shrugged after lighting up outside a store were he bought cigarettes. "I'm not sure what is changing now but I don't plan to quit," he said.