The Swiss intelligence service reported on Friday that it cooperated with Dutch and British partners to defeat a plot with Russian spies that were expelled from The Hague – the headquarters of the international chemical weapons watchdog, the OPCW.
The FIS statement followed newspaper reports in the Netherlands and Switzerland, claiming that two men were suspected of targeting a chemical laboratory near the Swiss city of Bern. The laboratory tested the traces of the nerve gas that was used in the Salisbury attack on the former Russian double agent Sergei Skripal in March.
"The Swiss authorities are aware of the case of Russian spies discovered in The Hague and expelled from the same place", according to the FIS statement. "The Swiss Federal Intelligence Service (FIS) participated actively in this operation together with its Dutch and British partners.
"The FIS thus contributed to preventing illegal actions against a critical Swiss infrastructure."
The Swiss laboratory in Spiez works on behalf of the OPCW. It has investigated chemical attacks in Syria and confirmed the UK claims that a nerve gas made by Russia, derived from a family of nerve products known as novichok, was used in the Salisbury attack.
The attack left Mr. Skripal, his daughter Yulia and a policeman seriously ill. British police say it accidentally led to the death in July of Dawn Sturgess and the contamination of her partner Charlie Rowley, who may have picked up a discarded perfume bottle with the novichok.
In the past few months, the laboratory was alerted to computer hacker "attack attempts from different sides" and abuse of his e-mails, according to a Swiss official, but the laboratory would not comment on the expulsions in The Hague.
The Tagesanzeiger in Switzerland and the NRC Handelsblad, which reported the story for the first time on Friday, wrote that two Russian spies wanted to "spy on" the Spiez laboratory, but were arrested in The Hague in the spring. It was reported that security equipment had also been seized.
Tagesanzeiger noted that it was unclear why the spies had been sent back to Russia, instead of being charged in the Netherlands or handed over to Switzerland. It was also not clear what they were doing in The Hague, although it noted that the OPCW was established here.
The Dutch General Intelligence and Security Service declined to comment on the reports. British security officials also refused to comment on the reports or statement from the Swiss FIS.
The news came a day after the two Russians accused of the attempted murder of Mr. Skripal on the Russian state television to denounce any involvement in the attack and said they were just tourists .
Although Alexander Petrov and Ruslan Boshirov told RT, an English news channel, that they had traveled to Switzerland for the new year, it is not thought that they are the same men who are being detained a few months later and are being expelled from the Netherlands.
When he spoke in Berlin, Sergey Lavrov, the Russian Foreign Minister, said he had no information about the detention.
"I can not even imagine that such an event, in which representatives of the three countries participated, could not be left out of the media", he said after conversations with his German colleague. "If facts are presented to us, we might be able to comment on that."
Mr Lavrov added that the recent British accusations against Russia seemed to have been motivated by the desire to "turn European partners against us" and to ward off the political pressure of the Brexit. "This is done because of Brexit," he said.
The Russian embassy in Switzerland said that he was not aware of the incident either.
"This would have happened six months ago, why did they just write about it?" That's very suspicious, they call anonymous sources, and it's all a big question, "an anonymous representative told the Interfax news service.
The Russian foreign intelligence service, the SVR, said it would not comment.
Additional reporting by Henry Foy in Moscow and Tobias Buck in Berlin