Leading Russian miners came under sustained selling pressure today as risks increased that their access to international finance and markets could be threatened.
Gold producer Polymetal was the biggest faller in the FTSE 100, losing over 35% of its share value to reach a four-year low.
Polymetal said in a press release on monday that its mines in Russia and Kazakstan were operating normally.
"The rapid deterioration in the situation in Ukraine has led to a material increase in possibility of additional and more severe sanctions to be imposed by the EU, the UK and the US," Polymetal said. "The scope and impact of these new potential sanctions (and any potential counter-sanctions) is yet unknown, however they might affect key Russian financial institutions as well as mining companies."
"Polymetal believes that targeted sanctions on the Company remain unlikely."
Polymetal was trading in London at £7.04, down 35.8% or £3.93, at time of writing.
Other major Russian mining firms impacted included gold miner Petropavlovsk which lost 24% in value to trade at £10.46 a share, down £3.24.
Steelmaker Evraz, controlled by Russian businessman Roman Abramovich, shed 27% in value to trade at £1.81, down £0.65.
EN+ was trading at $8.80 in London, down 6.9%.
Mining firms listed on the Moscow Exchange, including Polyus, Norilsk Nickel and Severstal also posted losses of between 10-20% of their share value before the exchange suspended trading on all of its markets "until further notice".
An estimated $250 billion of Russian stock market value was lost before the decision to suspend trade.
The ruble hit its lowest ever level against the US dollar.
The losses could become more widespread as the US and its allies announced additional sanctions against Russia.
US President Joe Biden said he would impose "severe sanctions" on Russia after Russia launched the single largest military attack against another in Europe since the Second World War.
Biden condemned the incursion as an "unprovoked and unjustified attack." "The United States and its allies and partners will respond in a united and decisive way."
Details of possible US sanctions are expected to be announced later Thursday.
The EU and the UK have also promised tighter sanctions against Russia and the G7 will also meet to coordinate policy.
European Commission President Ursula von der Leyen said the EU planned "massive and targeted" sanctions, aimed at Russia's financial sector, the freezing of Russian assets and technology export banks to the country.
Global equity markets opened lower on the attack and the gold price rallied as a safe-haven asset to its highest level in 13 months. Oil rallied to its highest level since 2014.
