British Prime Minister Boris Johnson said he would aim to cut Russia off from the U.K.'s financial markets as he announced a new set of sanctions in response to President Vladimir Putin's operation in Ukraine.

The sanctions include freezing the assets of all major Russian banks, including VTB Bank, the nation's second-biggest bank, Johnson said Thursday. Britain also plans to bar Russian companies and the Russian government from raising money on U.K. markets.

Britain will also ban the export of a wide range of high-tech products, including semiconductors, to Russia and bar the nation's flagship airline, Aeroflot, from landing at U.K. airports.

(With input from agencies)