Prime Minister David Cameron said on Thursday Britain will be "toughening" up its response to Russia after a public inquiry implicated President Vladimir Putin in the assassination of Alexander Litvinenko.
The Tory leader stopped short of threatening to end ties with Russia, noting the UK must have "some sort" of relationship with Moscow.
However, Cameron promised future dealings with Russia would be carried out with "clear eyes and a very cold heart" after the publication of Sir Robert Owen's report that concluded Putin "probably" signed off the fatal poisoning of Litvinenko, who died from ingesting radioactive polonium in London in 2006.
Marina Litvinenko speaks outside The High Court after publication of the inquiry into the death of her husband Alexander Litvinenko, on January 21, 2016 in London, England
Speaking in Davos, Cameron called the state-sponsored murder "absolutely appalling," adding that the report confirms what "we have always believed.”
In response, Maria Zakharova, a spokeswoman for the Russian foreign ministry, said: “We regret that a purely criminal case has been politicised and has darkened the general atmosphere of our bilateral relations.”
“Taking this into account, there were little grounds to expect that the final report of a process that was politically motivated and highly opaque, and prepared with a pre-determined ‘correct’ result in mind, would suddenly turn out to be objective and balanced,” she added.