Russian spies are targeting organisations trying to develop a coronavirus vaccine in the UK, US and Canada, security services have warned.
The UK's National Cyber Security Centre (NCSC) said the hackers "almost certainly" operated as "part of Russian intelligence services".
It did not specify which organisations had been targeted, or whether any information had been stolen.
But it said vaccine research had not been hindered by the hackers.
Russia has denied responsibility.
"We do not have information about who may have hacked into pharmaceutical companies and research centres in Great Britain. We can say one thing - Russia has nothing at all to do with these attempts," said Dmitry Peskov, a spokesman for President Putin, according to the Tass news agency.
The warning was published by a international group of security services:
- the UK's NCSC
- the Canadian Communication Security Establishment (CSE)
- the United States Department for Homeland Security (DHS) Cyber-security Infrastructure Security Agency (CISA)
- the US National Security Agency (NSA)
One expert said it was "plausible" that, despite the Kremlin's denials, Russian spies were involved.
"The received wisdom is that in cyber-space, attribution is difficult but not impossible," commented Emily Taylor from the Chatham House think tank.
"Usually the security services are much more hedgy in their language if they think there is any doubt.
"Cozy Bear [the named group] has been implicated in past cyber-attacks and has left quite a trail, and there are fairly good links to the Russian state itself."
Source : 2020 BBC