WASHINGTON (AP) — President Joe Biden on Thursday announced a new round of sanctions targeting Russia after its invasion of Ukraine, charging that Russian leader Vladimir Putin “chose this war” and that his country will bear the consequences of his action.

The sanctions target Russian banks, oligarchs, and high-tech sectors, Biden said. The United States and its allies will block assets of four large Russian banks, impose export controls and sanction oligarchs

The penalties fall in line with the White House’s insistence that it would look to hit Russia’s financial system and Putin’s inner circle, while also imposing export controls that would aim to starve Russia’s industries and military of U.S. semiconductors and other high-tech products.

Biden, for now, held off imposing some of the most severe sanctions, including cutting Russia out of the SWIFT payment system, which allows for the transfers of money from bank to bank around the globe, or Russia’s energy sector.

Biden announced the sanctions as Ukraine’s government reported mounting casualties as Russian forces attack from the east, north and south.

Hours before the attack started, White House press secretary Jen Psaki on Wednesday ticked through a list of factors the Biden administration is watching, describing recent trends of rising borrowing costs for the Russian government, falling foreign investment in the country, increasing weakness of the ruble and shrinking fortunes for the “super-rich.”

She added that all of this had transpired “before the bite even takes place” from the new sanctions that the U.S. and its allies started to roll out Tuesday. After Putin announced the launch of military operations against Ukraine, President Joe Biden promised the U.S. and allies would announce “further consequences” Thursday against Russia for its “needless act of aggression.”

Experts with knowledge of how the U.S. imposes sanctions say the biggest determinant of the success of such measures won’t be in the valuation of Russian markets, the ruble or other assets.

“To be honest, there aren’t any formalized systems, processes or procedures where Treasury actually makes that assessment, so that’s an interesting shortcoming, but it’s a reality,” said Adam Smith, who served in the Obama administration as senior adviser in Treasury’s Office of Foreign Assets Control. “The bigger question is are these going to change President Putin’s mind.”

Smith stressed that the market costs of sanctions shouldn’t be the only measure of success but they should also include consideration of what they might have prevented.

Citing the limited round of 2014 U.S. and European sanctions issued on various individuals and entities, Smith said Putin “took Crimea, but theoretically without those 2014 sanctions they could’ve gone into Kyiv.”

He said Treasury and the administration juggle many challenges, but “the task of measuring success is somewhat of a fool’s errand.”

The administration, in its first tranche of sanctions Tuesday, moved to cut off Russia’s government from Western finance, sanctioning two banks and blocking it from trading debt on U.S. and European markets. On Wednesday, Biden allowed sanctions to move forward against the company that built the Russia-to-Germany Nord Stream 2 gas pipeline and against the company’s CEO.

Nicholas Mulder, a professor of modern European history at Cornell University, says there are sometimes concrete measures of successful sanctions. He cited the restrictions on Iran’s growth, particularly from 2011 to 2015, when crude oil exports dropped by more than half.

In April 2015, then-Treasury Secretary Jack Lew said Iran’s economy had shrunk by 20% due to sanctions, according to a Congressional Research Service report.

But Mulder says that since Russia is a massive economy, the mathematics on sanctions enforcement and their success will look different, saying “it quickly becomes difficult in terms of repercussions on global markets.”

That’s why sanctions are often imposed on individuals, not an entire economy.

One example analysts have cited of how sanctions can work is China’s Huawei Technologies Ltd., the biggest global supplier of telecom switching equipment and once a top smartphone brand. American officials say it is a security risk and might help Chinese spying, an accusation the company denies.

Huawei is barred from buying most U.S. components and technology under a 2019 order by then-President Donald Trump. The loss of Google’s popular music, maps and other services crippled its smartphone business. Huawei, the top-selling smartphone maker in early 2020, sold its lower-priced phone brand Honor and has fallen out of the global top five.

U.S. and European sanctions could take a similar approach, barring export of electronic components that Russia’s defense industry and economy need but can’t produce themselves.

William C. Wohlforth, faculty director at the Dartmouth Institute for Global Security, said the most recent financial penalties should be viewed as a “warning shot across the bow about what could be done.”

“The only indicator that matters is whether it deters Putin from further moves in Ukraine,” he said. “Sanctions on this or that oligarch will have zero effect.”

Mulder said measuring success will also be difficult as Asian economies now take on a larger chunk of trading with Russia than they had in 2014, when sanctions were imposed when Russia annexed Crimea from Ukraine.

“There are ways of adjusting trade,” Mulder said, given that non-European countries will maintain commerce with Russia.