Two Russian agents suspected of trying to spy on a Swiss laboratory were arrested in the Netherlands and expelled early this year, Swiss newspaper Tages Anzeiger reported on Friday, citing unnamed sources.
It cited the Swiss NDB intelligence agency as confirming the information it and Dutch paper NRC Handelsblad had gathered.
The NDB did not immediately respond to an email from Reuters seeking comment.
The Swiss paper said Swiss, Dutch and British authorities had worked together to foil the plot directed at the Spiez laboratory near Bern, where experts in nuclear, biological and chemical weapons work.
The lab has analysed suspected poison gas deployed in Syria and samples of a nerve agent that Britain has accused Russia of using to try to murder a former spy.
The paper said the two suspects were not the same men accused by Britain last week of trying to kill Sergei Skripal and his daughter in the England in March.