Earlier this year, the UN established an executive body on the committee in an effort to get more countries to comply with a 2001 Security Council resolution demanding that governments adopt legislation and take measures to stop the support and financing of terrorists.
Ruperez told a meeting of the Organization for Security and Cooperation in Vienna that the most effective way to stop terrorism is to strangle it -- to cut off training facilities and sources of terrorist funding, such as drug smuggling and human trafficking. He warned that international terrorism is preparing for an "all-out war in which it will show no mercy" and said the world has to confront it.
Ruperez said he is disappointed that there has not been more progress in building a united front. "Too many principles remain applicable only in theory," he said. "Too many conventions have not yet been incorporated into the domestic law of some individual states."
Ruperez said countries should not wait until a terrorist attack occurs before taking action. He said strict implementation of agreements on international cooperation and information-sharing can prevent attacks before they occur.
"The fight against terrorism should be mainly a preventive fight. Prevention is law enforcement. Prevention is certainly legal measures. Prevention is ratification of legal instruments -- that is, on police cooperation [and] intelligence cooperation because, after all, that's the information we need to stop them from doing what they are trying to do," Ruperez said.
UN officials estimate there are more than 80 active terrorist groups around the world, including Al-Qaeda and its affiliates. Ruperez, who until May was Spain's ambassador to the United States, has personal experience with militancy. He was briefly kidnapped by Basque separatists in Spain in 1979.
Ruperez said the OSCE is at the forefront of the struggle against terrorism. One of the latest initiatives of its anti-terrorism unit is a call for stronger cooperation in checking cargo carried across state borders in containers -- by sea, by rail, or in trucks.
The UN estimates that around 90 percent of the world's cargo is transported this way. It suspects that border checks on the contents of such containers are often lax. Such containers can be used to carry illegal immigrants, drugs, or weapons.
Ruperez said it is essential to eliminate these financial resources of terrorist groups.
"Anything which we could do in fighting against [human] trafficking, against money laundering, against drug trafficking or corruption, for instance, is something we are doing in the fight against terrorism, as well," Ruperez said.
Ruperez said terrorism must be fought in all of its manifestations. "Terrorists never give up," he said. "So we never give up either."