WASHINGTON has tightened the sanctions' noose on Vladimir Putin's senior advisers and a key Russian bank, banning them from operating in and travelling to the US.
The Russian president's chief of staff Sergei Ivanov and billionaires Arkady Rotenberg and Gennady Timchenko are among 19 people to be hit with sanctions in retaliation for country's annexation of Crimea.
Russian forces yesterday seized three Ukrainian warships in the Crimean port city of Sevastopol.
St Petersburg-based Bank Rossiya, which is used for personal deposits by senior Russian government officials and has £6bn in assets, will be "frozen out of the dollar," US officials said. It is chaired and partly-owned by Putin adviser Yuri Kovalchuk.
Russia retaliated by barring former US presidential contender, senator John McCain, colleagues Mary Landrieu, Dan Coats, Harry Reid and Robert Menendez from travelling to Russia.
House of Representatives Speaker John Boehner was also on the list along with senior Obama adviser Dan Pfeiffer and deputy national security advisers Ben Rhodes and Caroline Atkinson
Mr Boehner's spokesman said: "The speaker is proud to be on a list of those willing to stand against Putin's aggression."
Senator Dan Coats said: "While I'm disappointed I won't be able to go on vacation with my family in Siberia this summer, I am honoured to be on this list."
A Russian Foreign Ministry spokesman said: "Sanctions are a double-edged instrument and would hit the US like a boomerang. We will respond adequately to every hostile thrust."
Russian flags were raised on the seized Ukrainian vessels, and on a pier in Sevastopol, as they were taken by masked individuals.
The Ukrainian military said the forces used stun grenades as they stormed the corvette Ternopol.