US Treasury Secretary Jack Lew said in a radio interview Friday that sanctions imposed on Russia for actions in Ukraine are "having an impact."
"If you look at the conditions since we've started imposing sanctions, they're having an impact. Even the Russians are admitting that they're having an impact," Lew told the American Public Radio show Marketplace.
Russia "cannot continue to violate Ukraine's sovereignty ... without facing additional and more stringent sanctions. We are prepared to take action, and we are working with our international partners to make sure that when we do it, we do it in an effective way," he said.
Lew said that he doesn't believe that sanctions "are being taken lightly" in Russia.
"We have sanctioned some of the most significant people in Russia close to the president. We have sanctioned a bank that's the bank where they all bank at. We see many signs that it is having an effect."
The "goal is to hurt the Russian economy while doing the least damage necessary to the US and the global economy," said Lew. "We've made clear we're prepared to take tougher actions and prepared to absorb the consequences of that if we need to."
Lew also said that tighter sanctions would have an impact on the global economy.
"There's no question that when you stop doing business with a country as large as Russia, that there are effects outside the boundaries of the country," he said.
"There are American companies that are already feeling some of the pinch, and there are European businesses that are feeling some of the pinch. The real burden is being felt in Russia. And that's the goal: The goal is to affect the Russian economy."
The United States, Canada and the European Union imposed financial sanctions that included freezing the assets of dozens of Russian and pro-Russian officials following the annexation of Crimea.
On Saturday, the Group of Seven rich countries agreed to slap sanctions on Moscow as early as Monday over the Ukraine crisis.
The G7 nations said in a joint statement they would "move swiftly to impose additional sanctions on Russia."