Guatemala and the United Nations have signed a deal aimed at cracking down on the country's widespread lawlessness.
Insecurity is a major concern in Guatemala
The unprecedented pact will allow a UN-appointed commission to prosecute organised crime groups and clandestine security organisations in Guatemala.
Security issues were among the main concerns of ordinary Guatemalans during last year's presidential election.
Local media reports say that murders, assaults and kidnappings increased by more than 150% during 2003.
The agreement, which will run for two years, was signed on Wednesday by Guatemalan Foreign Minister Edgar Gutierrez and Kieran Prendergast, the UN under-secretary general for political affairs.
It is still subject to approval by the Guatemalan parliament.
The new commission will have powers to investigate, arrest and prosecute illegal armed groups, who are blamed for much of the violence in Guatemala.
Under the agreement, its chief would be appointed by UN Secretary-General Kofi Annan and would choose a team experienced in human rights and organised crime.
A UN spokeswoman said the deal was a first for the organisation and an admission by Guatemala that it needed help.
It was also hailed by US State Department spokesman Richard Boucher, who described it as "a courageous effort" on the part of Guatemala to deal with human rights abusers and organised criminal organisations.
Guatemala's 36-year civil war ended in 1996, but its legacy remains difficult to eradicate.
It is estimated that there are 1.5 million guns in circulation in a nation of 12.3 million people.