The UK government has issued a fresh warning about the security risks of using Russian anti-virus software.
The National Cyber Security Centre (NCSC) is to write to all government departments warning against using the products for systems related to national security.
The UK cybersecurity agency will say the software could be exploited by the Russian government.
Security firm Kaspersky Labs, accused in the US of being used by the Russian state for espionage, denied wrongdoing.
Kaspersky Labs is widely used by consumers and businesses across the globe (although they are not being advised to stop using the software) as well as by some parts of the UK government.
Officials stress they are not recommending members of the public or companies stop using Kaspersky products, which are used by around 400 million people globally.
It comes amid heightened concern about Russian activity against the UK. Last month, Prime Minister Theresa May warned the Russian state that it was acting against the UK’s national interest in cyberspace.
Following her warning, Ciaran Martin, chief executive of the NCSC, said Russia has targeted British infrastructure, including power and telecoms.
The concern is that the anti-virus software could be used by the Russian state for espionage.
Officials say the NCSC’s decision is based on a risk analysis, rather than evidence that such espionage has already taken place.