Oil prices at highest level for more than seven years
Oil prices have surged past $100 a barrel after Russian President Vladimir Putin launched a "special military operation" in the eastern Donbas region of Ukraine, BBC reported.
The price of Brent crude hit $102.30 a barrel at one point, the highest level in more than seven years, the report said.
Russia is the second biggest exporter of crude oil, and is also the world's largest natural gas exporter, BBC reported.
Stock markets fell, with the UK's FTSE 100 index opening down more than 2.6 per cent.
Earlier, stocks in Asia and had fallen sharply, while the Moscow Exchange suspended trading shortly after the rouble plunged to its lowest since early 2016.
The price of gold - which is considered a haven asset in times of uncertainty - rose 2 per cent.
Tina Teng, an analyst at CMC Markets, said: "We could see [oil] prices keeping the momentum."
Most of the oil and gas that the UK imports does not come from Russia, but it would nonetheless be affected by a rise in global prices.
In response to Russia's military action, European Union leaders said they would put more sanctions in place on Russia, BBC reported.
The European Council said it would "impose massive and severe consequences on Russia for its actions".
The US and EU had already imposed a series of sanctions in response to Putin's actions against Ukraine.