A law to ban the carrying of guns in public and control illegal ownership has come into effect in Brazil.
Huge anti-gun protests preceded the passing of the law
The law, passed by Congress in December, came into force on Friday after being signed by President Luiz Inacio Lula da Silva.
It will tighten rules on gun permits and create a national firearms register, with strict penalties for owning an unregistered gun.
A referendum will be held in 2005 on whether to ban gun sales outright.
About 40,000 people are shot dead each year in Brazil, mainly in urban shanty towns, giving the country one of the worst murder rates in the world.
Gun owners now have 180 days to register their weapons or surrender them to the police.
Thereafter, anyone with an unregistered gun faces a four-year prison term.
The law is also creating a programme whereby the government will purchase guns from people as an incentive to them to disarm, but Congress has not yet approved funding for this.
Only strictly defined groups of people - including police, security officials, target shooters and transport companies - will be able to obtain a gun licence.
The legal age for owning a gun is being raised from 21 to 25.
In October 2005, a national referendum will ask: "Should the sale of arms and munitions be prohibited in Brazil?"
More than 50 other gun control bills have come before Congress over the years and failed to be passed.
Brazil's arms industry is the world's sixth largest, and strong lobbying has in the past blocked any changes to the law.
Critics of the bill say that it will not stop criminals from buying weapons illegally while depriving ordinary citizens of the means to defend themselves.
However, campaigners say that public opinion is now overwhelmingly in favour of gun control.
Over 100 police officers have been shot dead in Sao Paulo alone, and thousands of civilians die in incidents involving firearms in the country every year.