Domestic terrorism often has spill-over effects into other countries and linkages with foreign terrorist groups are not uncommon. Innovations in global communications have given some local groups international standing, while internationally operating groups use today's rapid international transportation to hit, run and hide. Perpetrators of terrorism in one country frequently use other states as safe havens or for fund-raising. They sometimes receive training abroad and use foreign countries for staging terrorist acts or as launching bases for their operations elsewhere. Victims of domestically oriented acts of terrorism are often foreign business people, diplomats or tourists.
Terrorists sometimes hide among emigrant diasporas and refugee communities.
Some terrorist organizations are partly engaged in legitimate trade or in illicit smuggling of drugs and weapons. Acts of terrorism are usually preceded by less violent forms of protest and conflict. Yet no early warning system currently exists. Since terrorism is a globalized phenomenon, it is a key task of the TPB to promote international cooperation in addressing this problem. The TPB works closely with the UN Centre for International Crime Prevention , which is also based in Vienna.