BRUSSELS — Two Russian spies caught in the Netherlands and expelled had been plotting cyber sabotage of a Swiss defense laboratory analyzing the nerve agent used to poison a former Russian agent in Britain, Swiss officials said Friday.
The story — first reported by the Dutch newspaper NRC and the Swiss newspaper Tages-Anzeiger, and confirmed by Swiss officials — adds a new dimension to the charges by Western governments that the Kremlin is waging a sophisticated and unconventional campaign to work its will abroad, and undermine adversaries and their alliances.
Britain contends that Russia sent two other spies to a quaint English cathedral city in March, carrying a military-grade poison to assassinate a turncoat former colleague, Sergei V. Skripal, which the Kremlin denies. The two men, publicly identified and charged by the British authorities, appeared on Russian television on Thursday to deny involvement in the poisoning that sickened Mr. Skripal and three others, and killed one person, insisting that they were sports nutritionists, not spies.
The Dutch authorities declined to comment on any expulsion of Russians or any plans for a cyber attack. The Swiss described the events as having taken place “earlier this year” but declined to be more specific. It was not clear if the Russians were among the diplomatic employees — many suspected of being intelligence agents — expelled by Western governments in retaliation for the Skripal attack.
The two Russians, whose names have not been made public, came to the attention of the Swiss authorities during an investigation that began in March into “suspicion of political espionage,” said Linda von Burg, a spokeswoman for the Office of the Attorney General of Switzerland.
That led to a joint investigation by Swiss, Dutch and British intelligence services, which concluded that the two Russians, working in The Hague, were spies for the Russian government and were preparing “illegal actions against a Swiss critical infrastructure,” according to Isabelle Graber, a spokeswoman for the Swiss Federal Intelligence Service.
She did not specify the intended target. But Andreas Bucher, a spokesman for the defense laboratory in the Swiss town of Spiez, confirmed that the laboratory had been the intended target. Mr. Bucher said he did not know about the Russians being identified, detained or expelled from the Netherlands.
The Dutch media reports said that when they were intercepted by the Dutch military intelligence service, the two Russians had cyber tools for sabotaging the laboratory.
Sergey V. Lavrov, the Russian foreign minister, said on Friday that he would not comment until more information was available. Russia’s foreign intelligence service declined to comment.
The Spiez laboratory is part of the Swiss Federal Office for Civil Protection, which falls under the Swiss Defense Department, and is the designated lab in Switzerland for several international organizations, including the United Nations.
The lab was one of two designated by the Organization for the Prohibition of Chemical Weapons to provide independent analysis of the poison used against Mr. Skripal. The organization, which monitors compliance with a global treaty on chemical weapons, confirmed the British conclusion that the chemical belonged to a class of nerve agents developed by the Soviet Union, known as Novichok.
The lab also analyzed samples from the chemical attack near Damascus, Syria, in 2013 that killed more than 1,000 people. The United Nations concluded that the toxin in that attack was another nerve agent, sarin. Western governments have said it was used by forces of President Bashar al-Assad of Syria, which Russia supports in the Syrian civil war.
Workers at the Spiez lab need security clearances and most are Swiss nationals, though some are foreign fellows or visiting researchers, according to Mr. Bucher, the spokesman.
“We have indications of several attacks against our institutions, including possible cyber attacks in the last few months,” Mr. Bucher said. “But we took the necessary precautions and haven’t been compromised.”
Mr. Skripal, a former officer in Russian military intelligence, was imprisoned by the Russians for selling information to Britain. In 2010, he was sent to Britain in a spy swap, and settled in Salisbury, a small city in southwestern England famous for its church spire.
On March 4, he and his daughter, Yulia S. Skripal, who was visiting from Russia, became seriously ill, as did one of the police officers who responded, Detective Sgt. Nick Bailey. It was quickly determined that a nerve agent was the cause, and parts of Salisbury were shut down amid a widespread search for traces of the poison, as local residents waited in fear for the results.
British investigators concluded that the toxin was Novichok, applied to the handle of Mr. Skripal’s front door, and long before they named the suspects they would eventually charge, officials said Russia had been responsible. Several Western countries expelled Russian officials, and denounced the attack as a violation of international norms, like Russia’s aggression in Ukraine, its interference in other countries’ elections, and assassinations and cyber attacks carried out abroad.
Almost four months after the Skripal attack, two more people became seriously ill, apparently from handling a discarded bottle of the nerve agent. One of them, Dawn Sturgess, died, and the other, her boyfriend, Charlie Rowley — like the Skripals and Sergeant Bailey — recovered.
Oleg Matsnev contributed reporting from Moscow.