The next round of US sanctions against Moscow over Ukraine will target Russia's defense industry as well as individuals and companies close to President Vladimir Putin, a senior US official said Sunday.

"Starting this week, in coordination with our allies and partners, we'll be exerting additional pressure on the people closest to him, the companies they control, the defense industry. All of this," deputy national security adviser Tony Blinken said on CNN's State of the Union.

In a separate interview with CBS's "Face the Nation," Blinken said high technology exports to the Russian defense industry would be affected.

President Barack Obama said earlier Sunday the sanctions being drawn up by G7 countries were a punishment for Moscow's "provocation" in eastern Ukraine.

"It is important for us to take further steps sending a message to Russia that these kinds of destabilizing activities taking place in Ukraine have to stop," Obama said in Kuala Lumpur.

Blinken, however, made clear that Washington would not meet Ukraine's demands for weapons despite menacing Russian military exercises on its borders.

"Here is the bottom line. We could send weapons to Ukraine. It wouldn't make a difference in terms of their ability to stand up to the Russians," he said.

Instead, he said Washington would focus economic aid to Kiev, with an estimated $37 billion being rounded up by Washington, the IMF, World Bank and others.

"We need to be deliberate and do this in coordination with our partners," he said.

Republican lawmakers criticized the administration's approach as too little, too late, and called for sanctions that strike directly at the Russian economy.

"To me, hitting four of the largest banks there would send shock waves into the economy," said Bob Corker of Tennessee, the ranking Republican on the Senate Foreign Relations Committee.

"What I fear is all we're doing is tweaking folks," he said, adding that the sanctions targeting individuals were "not creating the kind of pain within Russia that will cause Putin to change," he said.