The White House on Friday refused to comment on reports that Russian President Vladimir Putin's personal wealth could be targeted if the West were to move ahead with additional sanctions over Ukraine.
"I'm not going to get into foreshadowing particular individuals or entities that the United States may target," national security adviser Susan Rice told reporters at the White House. "But let me just say we've been clear that there are additional individuals, officials, close associates of senior leadership, oligarchs and those entities that they are associated with that remain very much potential targets of additional sanctions."
Putin's actual holdings are a tightly held secret, and the extent of his holdings are difficult to estimate. But a threat of trying to freeze the Russian president's personal assets could have played a role in a deal brokered Thursday by foreign ministers from the U.S., Ukraine, Russia and European Union.
Under that deal, Western powers agreed to hold off on additional sanctions if pro-Russian separatist groups agree to disarm and leave occupied government buildings in Eastern Ukraine.
President Obama expressed guarded optimism that deal would work during a press conference on Thursday.
"My hope is that we actually do see follow-through over the next several days, but I don't think — given past performance — that we can count on that," Obama said.
He added that the U.S. had "to be prepared to potentially respond to what continues to be, you know, efforts of interference by the Russians in Eastern and Southern Ukraine."
Rice said Friday she did not think it was "constructive" to "start to get into naming individuals that may be on our sanctions list."
"In fact, if you know how sanctions enforcement works, to presage that is counterproductive," Rice said.
State Department spokeswoman Jen Psaki also wouldn't say if the U.S. was considering sanctions against Putin.
"I don't have any new update to tell you, just to convey that there are dozens of individuals who have played unhelpful roles who we could certainly sanction if warranted," Psaki said.
Last month, a senior administration official said it was "highly unusual and rather extraordinary" to penalize foreign leaders, but the White House did not rule out taking action against Putin.