BBC News with Stewart Macintosh

President Putin has signed an order recognizing Crimea

 as an independent and sovereign state with immediate effect,

 it comes shortly after the Untied States and the European Union 

imposed targeted sanctions on key Russian and Ukrainian 

officials connected with Moscow's intervention in Crimea.

  Mr. Putin is to address both Houses of the Parliament 

and the nation on Tuesday. Artyom Liss is

 the head of the BBC Russian service.

 “The authority exists to apply sanctions to a variety of individuals

 and entities, we are not going to rule out individuals 

or rule out actions except to say that there will be costs imposed

 on Russia. Additional costs imposed

 on Russia if Russia does not change direction here when it

 comes to how it's handling the situation in Ukraine.”

 President Obama said he wanted to make it clear there would

 be consequences for provoking the secession and said

 further sanctions could again be announced.

 But he stressed there was still a path to

 solve the crisis diplomatically.

 White House spokesman Jay Carney when asked by journalists

 whether sanctions could be imposed on Mr. Putin,

 gave this response. “The authority exists to apply

 sanctions to a variety of individuals and entities,

 we are not going to rule out individuals or rule 

out actions except to say that there will be costs imposed on Russia.

 Additional costs imposed on Russia if Russia

 does not change direction here when it comes to

 how it's handling the situation in Ukraine.”

 Among those already targeted are senior Crimean officials,

 and deputy Russian prime minister,

members of the parliament and commands of the Russian Black Sea 

Fleet in Russia's Western and Southern military district,

 units of which are deployed in Crimea. 

The EU's Foreign Policy chief Catherine Ashton said those 

singled-out for travel and asset bans were responsible for

 threatening Ukraine's territory integrity and independence. 

The Russian deputy Foreign Minister Sergei Ryabkov

said US measures reflected it designed to 

impose its own unilateral unbalanced approach.