Swiss police raided several houses and searched a mosque in Switzerland's south as part of an investigation into suspected Islamist activity, federal prosecutors said.
More than 100 officers took part in the operation on Wednesday and arrested one man, the Office of the Attorney General (OAG) said in a statement.
The OAG said it was conducting criminal proceedings against two men, one with dual Swiss-Turkish citizenship and the other a Turkish citizen, based on suspicions of recruiting for Islamic State or associated groups.
One of the men was detained pending further enquiries, although the OAG did not specify which one.
The operation was part of an independent Swiss investigation and was unconnected to the truck attack at a Berlin Christmas market that killed 12 people in December, the OAG said.
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Anis Amri, the Tunisian asylum seeker who drove the truck, had several links to Switzerland, and may have obtained a gun in the country.
The OAG has opened its own investigation against "unknown" persons in relation to the Germany attack.
Neutral Switzerland is not a primary target for Islamist attacks because it is not part of the military campaign against groups such as Islamic State, but the security threat level has been elevated, the NDB federal intelligence service said in its annual report last year.
The Swiss took a suspected Islamist leader into custody last year in their first arrest of a senior figure from a Salafist ring based in the northern city of Winterthur.
Authorities said Wednesday's operation was not linked to Winterthur.
Swiss authorities believe more than 70 people have travelled to the Middle East to become jihadist fighters since 2001.
