In a report released Tuesday in Bern by Swiss Defense Minister Ueli Maurer, the FIS says it found 12 cases in which Swiss nationals left the country for "jihad areas" such as Somalia or Afghanistan/Pakistan to participate in terrorist activities.
The report also cited unconfirmed reports of the return of some of them to Switzerland, which it said demonstrates the need for enhanced laws to help deal with the threat, the Swiss News Agency reported.
Maurer told reporters he would propose a new law sometime this year that would seek to improve public safety by giving the security services more power and resources, which the FIS insists can be done while protecting fundamental rights.
The seven-member Swiss Federal Council, which serves as the country's executive, in 2007 proposed allowing federal agents to monitor communications such as phone calls and e-mails and to carry out surveillance on private property, if necessary by tapping phones and carrying out covert surveillance of online computer activities.
The Swiss Parliament, however, rejected it, citing civil liberties concerns.
Intelligence services in Switzerland are not allowed to monitor political activities unless they can demonstrate a concrete link to violence.
But there are always gray areas, Maurer said.
The FIS report concedes the terrorism threat to Switzerland overall remains small but adds there are some worrisome trends, such as the impact of the Arab Spring.
The agency warned even though the mass movements to depose Arab dictators have been backed by Switzerland, their ultimate outcomes are unpredictable, public broadcaster SRG SSR reported on its Swissinfo Web site.
"At worst, instability, economic setbacks and violent confrontations will proliferate and possibly lead to new international interventions or lay the ground for new fundamentalist or authoritarian governments," the report said, adding Swiss embassies in the southern and eastern Mediterranean could be at risk.
"Risks of terrorism, and the outflow of weapons resulting from the destabilization of countries, disruption of trade and energy supplies, handling of international sanctions, dealing with assets belonging to the ex-leaders, and migration from crisis areas to Europe have become increasingly significant problems," the report said.
Also cited were possible security threats posed by nuclear proliferation, domestic extremism on the left and right, and the effects of the European debt crisis.
The activities of terror-liked groups such as the Kurdistan Workers' Party and the Sri Lankan Liberation Tigers of Tamil Eelam drew concern as well.
FIS chief Markus Seiler, in an interview with Swiss daily Le Temps, said his agency is probing reports the Kurdish terrorist group, known by its initials PKK, is conducting training camps on Swiss soil.
"As noted in our 2012 status report, we have not yet confirmed information about PKK boot camps, but we are investigating the matter," he said. "We had already found camp activities in Switzerland a few years ago."
Seiler said a reported split among the leadership of the PKK "could actually increase tensions. The threat of violent actions against Turkish targets such as demonstrators, groups, private businesses and official representation still exists."
A leadership fight at the top of the PKK "would result in a heightened threat of terrorist actions in Turkey and would have consequences for Europe and for Switzerland," the spy chief said.
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