WASHINGTON (Reuters) - The United States will impose further sanctions on Russia on Monday over the crisis in Ukraine and they will include high-tech exports to Russia's defense industry, a White House official said on Sunday.

White House deputy national security adviser Tony Blinken said the sanctions are designed to punish Russia for not living up to an agreement to de-escalate the situation in eastern Ukraine, where armed pro-Russian separatists have taken control of about a dozen government buildings.

The White House had previously said "cronies" of Russian President Vladimir Putin and the companies they control would be targeted with sanctions.

"We're going to save a little news for Monday but what I can tell you is this," Blinken said on CBS's "Face the Nation" program.

"We will be looking to designate people who are in his inner circle, who have a significant impact on the Russian economy. We'll be looking to designate companies that they and other inner circle people control. We'll be looking at taking steps, as well, with regard to high-technology exports to their defense industry. All of this together is going to have an impact."

He did not elaborate.

The leaders of the Group of Seven major economies agreed on Saturday to impose further sanctions on Russia over the Ukraine crisis.

The European Union is also expected to announce sanctions as early as Monday targeting individuals and companies. Washington is more hawkish on further sanctions than Brussels, and this has caused a degree of impatience among some U.S. officials with the European response.

Speaking during a visit to Malaysia, U.S. President Barack Obama said any decision on whether to slap sanctions on sectors of the Russian economy at a later time would depend on whether the United States and its allies could find a unified position on how to proceed.

Blinken said the sanctions imposed on Moscow after its annexation of Crimea have hurt the Russian economy.

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"We've already seen a significant impact of the pressure we've exerted on Russia over the last several weeks. Their financial markets are down 22 percent since the beginning of the year, the rouble is at the lowest level ever," he said.

The Western-backed government in Kiev accuses the Kremlin of planning to invade the east of Ukraine, and of preparing the ground by training and supporting the armed separatists.

Russia denies it is to blame for the crisis. It says Ukraine's east is rising up in a spontaneous protest against what it calls an illegitimate government in Kiev which is mounting a "criminal" operation to suppress dissent.

(Reporting by Eric Beech; Editing by Jim Loney and Stephen Powell)