The U.S. plans to slap new sanctions on Russia this week that the White House says will target people and companies inside President Vladimir Putin's "inner circle."
Washington also plans to impose new restrictions on high-tech exports to Russia's defense industry in a move aimed at punishing Moscow for not living up to an agreement to defuse the situation in eastern Ukraine, where armed pro-Russian separatists seized about a dozen government buildings.
The leaders of the Group of Seven major economies agreed on Saturday to swiftly impose further sanctions on Russia over the Ukraine crisis. The U.S. and European Union previously imposed limited sanctions on Russian officials over Moscow's annexation of Crimea.
Washington could announce its new list of sanctions as early as Monday, senior U.S. officials have said.
The White House said previously that "cronies" of Putin and the companies they control would be targeted with sanctions.
"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," White House deputy national security adviser Tony Blinken said Sunday.
"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," Blinken said on CBS' "Face the Nation" program.
The EU is also expected to announce sanctions as early as Monday targeting individuals and companies. Washington is more hawkish on further sanctions than Brussels, which has caused some impatience among some U.S. officials with the European response.
"We're going to be in a stronger position to deter Mr. Putin when he sees that the world is unified and the U.S. and Europe is unified rather than this is just a U.S.-Russian conflict," U.S. President Barack Obama told reporters during a visit to Malaysia.
The top Republican on the U.S. Senate Foreign Relations Committee, Bob Corker, said the Obama administration's sanctions on Russian individuals had not gone far enough.
"I think we need to put sectoral sanctions in place," Corker told CBS. "To me, hitting four of the largest banks there would send shockwaves into the economy," as would targeting Russian gas giant Gazprom, 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, saying Ukraine's east is rising up in a spontaneous protest against what it calls an illegitimate government in Kiev.