UK's main stock indexes plunged on Thursday, tracking a sharp drop in global equities as investors shed riskier assets, after Russian forces launched an invasion of Ukraine.

The benchmark FTSE 100 index fell 2.6% at 0805 GMT, while the domestically focussed mid-cap index slumped 2.9%.

Russia fired missiles at several cities in Ukraine and landed troops on its coast on Thursday, officials and media said, after President Vladimir Putin authorised what he called a special military operation.

FTSE 100 climbs as Barclays, consumer staples boost sentiment

The United States and its allies will impose "severe sanctions" on Russia, US President Joe Biden said.

However, losses on the commodity-heavy FTSE 100 were smaller than its European peers, helped by Shell gaining 0.6% as oil prices surged, while precious metals miner Fresnillo jumped 6% as gold prices surged with investors fleeing to safe-haven assets.

Britain's largest high street bank Lloyds fell 6.8% after missing profit expectations.