ZURICH (Reuters) - Swiss authorities have taken a suspected Islamist leader into custody, broadcaster SRF reported on Wednesday, calling it the first arrest of a senior figure from a Salafist ring based in the northern city of Winterthur.
The man, a Muslim convert identified only by the letter S, is being held in investigative custody while authorities check his suspected role in radicalising and recruiting young people to fight with Islamic State in Syria and Iraq, the report said.
Federal prosecutors would not confirm the report. In a statement, they said that SRF had not respected a request to delay its report by a few weeks to avoid jeopardising "an open criminal investigation surrounding jihadist-motivated terrorism".
After deadly jihadist attacks in France and Belgium, Swiss authorities are monitoring the social media activity of about 400 possible jihadists who might pose a security threat, the NDB federal intelligence service said last month.
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 nonetheless, the NDB's annual report said.
Authorities have been closely tracking suspected jihadists who return to Switzerland from countries, Syria in particular, where they are believed to get training in carrying out attacks.
Swiss authorities believe more than 70 people have travelled to the Middle East to become jihadist fighters since 2001.
A Swiss court in April sentenced three Iraqis for terrorism offences, a verdict that the senior prosecutor said should send a message to jihadists not to see the country as an easy target.
The three main defendants, who had denied wrongdoing, were arrested in early 2014 on suspicion of planning terrorist attacks and helping Islamic State militants enter the country.
Switzerland said last month it was seeking to revoke the citizenship of a 19-year-old Swiss-Italian man identified by a former employer as a suspected jihadist who travelled to Syria to join Islamic State.
Separately on Wednesday, the Swiss government said it had taken steps to improve counter-terrorism measures, including plans to allow police to conduct covert surveillance and make suspects regularly report to a police station.
(Reporting by Michael Shields; Additional reporting by Joshua Franklin; Editing by Richard Balmforth)