The conference, hosted by the United Nations and the Organization for Security and Cooperation in Europe, was closed to media and had been scheduled before the train station attacks in Madrid. Organizers said it began with a minute of silence in tribute to the victims.
Meeting documents made available to The Associated Press described a fresh effort to coordinate operations and ensure that counterterrorism measures can, as one senior official put it, "drain the swamp."
"If terrorists and state sponsors of terrorism have globalized their operations, we as international organizations combating terrorism must do so as well," said Brian Woo, chief of the OSCE's Action Against Terrorism unit.
The day's meeting also included the heads of the U.N. Counter-Terrorism Committee, the U.N. Office on Drugs and Crime, the European Union's Counter-Terrorism Group, and experts from Interpol, the International Criminal Police Organization, the World Bank, the International Monetary Fund and the Organization of American States.
A "Vienna Declaration" being hammered out at the conference warned that agencies risk overlooking some aspects of the terrorist threat while duplicating efforts on other fronts.
It did not elaborate, but said international experts were "concerned with the potential duplication of technical assistance ... while other priority areas may remain unaddressed," according to a copy of the draft obtained by AP.
"The danger of overlap and wasting precious resources is great," conceded Jan Kubis, secretary-general of the 55-nation OSCE, Europe's largest security organization.
The U.N. Counter-Terrorism Committee, formed by the Security Council in the aftermath of the Sept. 11, 2001 attacks, has been working to streamline the global effort to intercept terrorist plots.
The draft declaration stressed the need to make sure that counterterrorism efforts don't violate the civil liberties of law-abiding citizens.
A senior official involved in the talks denied that it was an implicit reference to the USA Patriot Act, which civil libertarians have criticized as too intrusive, or the United States' detention of suspects at Guantanamo Bay, Cuba, without charges or access to legal representation.
Experts were focusing on links between narcotics traffickers and terrorists and on the growing use of "non-banking conduits" — informal financial support networks that help terrorists bypass banks and avoid leaving a paper trail behind.
International and regional anti-terrorism agencies have piecemeal information on the underground financing of terrorist activities, but they need to share it to cut off the cash flow, Woo said.
Officials said the OSCE, Interpol, the International Office for Migration and other organizations were working more closely with the International Atomic Energy Agency to crack down on the illicit trade in radioactive materials that could be used to build radiological "dirty bombs."
The conference also was examining the threat posed by shoulder-fired rockets, which terrorists reportedly are trying to acquire to shoot down civilian jetliners, and efforts to tighten security along porous borders.