Two Russian spies were arrested while trying to spy in a Swiss laboratory where samples of Salisbury's novichok attack were tested, it has been claimed.
It is said that the two agents, who are not the men accused by Great Britain of carrying out the attack of neurotoxic agents, went to the Spiez laboratory in Switzerland earlier this year.
It is alleged that both carried equipment that they would have used to hack the computers of the laboratory, although the Swiss officials said that no data had been stolen.
The men were arrested in the Netherlands and the Swiss authorities are investigating, several media reported in Switzerland.
The two agents are accused of targeting Switzerland's Spiez lab (pictured) earlier this year in an alleged attempt to hack into the lab's systems, where Novichok's samples were tested.
Swiss, Dutch and British intelligence worked together to thwart the plan for the laboratory near Bern, which houses experts in nuclear, biological and chemical weapons.
The two men were returned to Russia after their arrest.
"The case of Russian spies discovered in The Hague and then expelled from The Hague is known to the Swiss authorities," a spokeswoman for the Swiss intelligence services told AFP.
The Swiss spy agency & # 39; participated actively in this operation in collaboration with its Dutch and British partners in the prevention of illegal actions against critical Swiss infrastructure & # 39; said.
The laboratory analyzed samples of Salisbury's nerve agent and also examined the chemical weapons suspected of being used by Syrian President Assad during the country's civil war.
It carries out analytical work for the Organization for the Prohibition of Chemical Weapons (OPCW), based in The Hague.
In April of this year, Moscow claimed that tests in the Spiez laboratory had found traces of a nerve agent produced in the West in the Salisbury samples.
The lab chiefs did not comment directly on the claim, but said they had no doubt that the British experts at Porton Down had correctly identified the novichok.
Swiss, Dutch and British intelligence worked together to thwart the plot to the lab (pictured) near Bern, which houses experts in nuclear, biological and chemical weapons
Today the Kremlin said it would consider any request from Britain to interrogate the two suspects in the Salisbury nerve agent attack.
The United Kingdom accused Alexander Petrov and Ruslan Boshirov of a plan to poison the former spy Sergei Skripal, but claim that they were visiting Salisbury as tourists.
They were widely ridiculed after they claimed they had been in Salisbury to visit the city's cathedral.
Britain says that the two men are officers of Russian military intelligence, the GRU, who traveled to the United Kingdom with false names.
They are not the men accused of trying to hack the Swiss laboratory.
Kremlin spokesman Dmitry Peskov said that any request from London to interview them would be considered in "strict compliance with the law", but so far Britain had rejected any offer to cooperate in the investigation.
The UK accused Alexander Petrov and Ruslan Boshirov (pictured) of a plan to poison the former spy Sergei Skripal, but claim they were visiting Salisbury as tourists.