Russia on Wednesday dismissed the latest warning from President Joe Biden, who said the previous day that the U.S. could seek to sanction President Vladimir Putin personally if he sends forces across the border to invade Ukraine. Putin’s spokesman said any such sanctions would be “destructive,” but not “painful” because, according to the Kremlin press secretary, Russia’s senior leaders don’t hold overseas bank accounts or assets.

Speaking with reporters on Tuesday, President Biden said that if Putin were to send the roughly 100,000 troops he’s massed along Ukraine’s borders into the U.S.-allied country, “it would be the largest invasion since World War II. It would change the world.”

Asked if his administration would sanction Putin personally, Mr. Biden replied: “Yes… I would see that.”

The president’s comment was the latest ratcheting up of tension between the U.S. and Russia over what the White House and its NATO allies believe are Putin’s possible plans to invade Ukraine, as his forces did in 2014 when they annexed Crimea.

CBS News senior foreign correspondent Holly Williams, reporting on Wednesday from Kyiv, said so far, Putin has appeared unmoved by the warnings from Mr. Biden and other NATO leaders. Even as the U.S. pours in weapons to better arm Ukraine’s forces and NATO deploys warships and troops to the region, there’s no indication that Russia is backing down.

Russia has continued carrying out military exercises along Ukraine’s borders on land, and with its naval forces at sea.

Kremlin spokesman Dmitry Peskov delivered the rebuttal to the latest warning from Washington on Wednesday. He was quoted by Russian state news agency RIA Novosti as attributing the notion of sanctions against Putin or other Russian leaders to “U.S. congressmen and senators who are not entirely familiar with this topic,” and who would have been wise to first consult “those who are professionally engaged in Russia.”

He said it had “long been prohibited for representatives of senior leadership and officials” to hold foreign assets. “Therefore, of course, such a formulation of the question is absolutely not painful for any one of the representatives of the top management.”

Putin is widely believed to hold significant financial assets, but his personal wealth remains a mystery. Whatever assets he does have are well hidden, and it’s unclear how much impact any new American sanctions might really have on the man who has led Russia for more than two decades.

The White House, while warning repeatedly for weeks that Russia would face “severe” and “unprecedented” sanctions if it invades Ukraine, has provided no detail on the further measures it’s considering, with allies or unilaterally.

Putin’s intransigence in the face of the warnings from the West has led to questions about whether a conflict is inevitable, and what his motivation for a hypothetical attack on Ukraine could be.

As Williams reports, Ukraine’s leaders have taken to the airwaves this week urging their nation to remain calm.

“Don’t worry, sleep well,” the defense minister said Tuesday. But the 79-ton planeload of American military equipment that landed in Kyiv — nearly 300 Javelin anti-tank missiles and other munitions — tells a somewhat different story. It was just the latest shipment of some $200 million worth of emergency military assistance coming from the U.S.

Even with the American help, Ukraine is massively outgunned and outnumbered by its giant neighbor to the east, however, and with the Russian troops just over their borders, Ukrainians’ fate may be in the hands of just one man: Putin. 

Russia’s soft-spoken strongman leader grew up in the USSR and went on to serve the Soviet Union as a KGB agent.

According to Mikhail Khodorkovsky, a Russian businessman and very public critic of Putin, the president “wants Russia to become like the Soviet Union again.”

“The most important thing for him is controlling the situation,” Khodorkovsky told CBS News. The businessman was convicted on corruption charges in Russia that many believe were politically motivated. After serving a decade in prison, he now lives in exile.

He said to understand the Russian leader, the U.S. must stop thinking of him as a president.

“You need to talk to him like with [a] criminal boss,” Khodorkovsky told Williams. He claims that Putin is attempting to recreate the Russian empire as a way of distracting ordinary Russians from their economic hardship, and he says Putin’s main goals are simple: Stay in power and enrich himself and his friends.

Williams told the Russian dissident it sounded like he was calling Putin the Tony Soprano of global politics.

“Exactly,” he replied. “I’ve said this to Western politicians time and time again… You are dealing with a mafia boss. If you want advice on how to talk to Vladimir Putin, ask your police.”

The current standoff on Ukraine’s border began, Williams noted, because Russia moved tens of thousands of its troops to that border. But Putin’s government insists Russia is the victim — threatened by alleged aggression from the U.S. and NATO.

Some analysts believe Putin does not want another democracy on Russia’s western flank with close ties to the U.S. and NATO, and is trying to threaten Ukraine back into Moscow’s orbit, and force the U.S. and its allies to let him have what he wants.