CHICAGO (AP) — Treasury Secretary Janet Yellen used a visit to Chicago on Wednesday to spotlight the Biden administration’s determination to strip Russian oligarchs of their wealth in response to Vladimir Putin’s invasion of Ukraine.

“We have made it a priority to go after oligarchs or Russian elites who are key to President Putin’s corrupt power,” Yellen said. She added that Treasury, along with the Justice Department and U.S. allies, plans to “uncover, freeze and seize their wealth around the world.”

Yellen was in Chicago the day after President Joe Biden’s State of the Union address to amplify his message as Cabinet members fanned out around the country. She made a point to stop at a bakery in the Ukrainian Village neighborhood as a show of support.

She followed that with a speech at the University of Illinois Chicago that suggested the sanctions against Russian companies and powerful individuals will only intensify after a series of salvos that began last week.

The sanctions have already had a crushing impact on the Russian economy, causing the ruble to plunge and forcing the closure of Russia’s stock market. By targeting oligarchs, the Biden administration is going after the elites who owe their fortunes to Putin and could possibly be used to pressure the Russian leader.

Biden, in his address Tuesday, briefly addressed oligarchs, saying, “We are coming for your ill-begotten gains,” pledging that the U.S. and European allies were looking to seize their yachts, luxury apartments and private jets.

Captain Jeff Palmer from United Yacht Sales says superyachts owned by Russian billionaires are reportedly on the move.

“There are rumors that these boats are running now to neutral territories, Palmer said Wednesday as a guest of NewsNation Now’s “On Balance.” “They’ve shut up their AIS systems, which is automatic identification systems, that give you your course speed (of) when it will arrive, where it was from. They are shutting that off. They’re running blindly now … trying to stay away from the authorities.”

On Wednesday, authorities in Germany seized Russian oligarch Alisher Umanov’s a 500-foot yacht, according to Forbes. That megayacht alone is worth an estimated $600 million. Five other megayachts are reportedly anchored or heading to the Maldives, which does not have an extradition treaty with the U.S.

Palmer said because these yachts are not armed with weapons, they are going to be easier to seize.

“They’re set to block camera photographs of celebrities on board. But as far as tactical, no, they’re not set for that,” Palmer said.