NAPLES, Italy -- UN Secretary General Boutros Boutros-Ghali opened a conference on cross-border crime Monday, branding mafia activity a threat to democracy and urging governments to join forces to fight off the growing menace of illegal gangs.


He told delegates from 138 countries to the three-day conference that the tentacles of "crime multinationals" had spread across the globe.


"In Europe, in Asia, in Africa and in America, the forces of darkness are at work and no society is spared," Boutros-Ghali said.


The conference, being held amid massive security in the crime-blighted southern Italian port of Naples, is the highest-level meeting the UN has ever called on organized crime.


It takes place at a time of mounting alarm at the speed with which traditionally clannish organizations such as the Hong Kong-based Triads, Italy's Mafias, the Japanese Yakuza and Russian groups are beginning to make deals with each other.


UN experts say international crime syndicates now turn over a combined $750 billion a year -- more than the economic output of most countries and much of it "laundered" through the global financial system.


Boutros-Ghali cited the collapse of communism and the disintegration of the Soviet Union, regional conflicts and social decay in countries of the Third World as developments which had all contributed to the explosion of organized crime.


"When order is in retreat, and when law, morals and democracy are under attack, all kinds of criminal ventures and deviant behavior may be spawned. This is what we are bound to work together to prevent," he said.


UN officials and the gathering's Italian hosts hope that participants in the Naples meeting will agree upon harmonized laws against organized crime and money laundering so that the mobs will have no "safe haven."


The conference is also due to consider ways to boost international cooperation, including on the exchange of police intelligence, and whether a new international convention is needed.