The U.S. is ramping up sanctions on Russia in retaliation for its ongoing attack on Ukraine, raising questions about Russian investment into the U.S. property market.

But Russian money is already spread through New York City real estate, and the New York Post outlined some of the biggest Russian-born investors in city properties, most of whom have direct connections to Russian President Vladimir Putin.

For example, Roman Abramovich, who owns Chelsea Football Club in the UK, has multiple homes connected to him, though he transferred about $92.3M in real estate to his ex-wife, Dasha Zhukova. In 2014, he started snapping up homes on 75th Street between Madison Avenue and Fifth Avenue, with 9, 11 and 13 East 75th St. now connected to him, and the Post reports he paid some $74M for the properties. He is also connected to property at 15 East 75th St., at a price of $16.5M, as well as the third floor of 215 East 75th St., at $900K.

These properties were transferred to Zhukova, who launched her own residential development firm in the city, called Ray, last year. The company is joining with L+M Development Partners to build a 21-story building with new theater space, retail and event space beneath 222 apartments called Ray Harlem at the corner of 125th Street and Fifth Avenue.

Oleg Deripaska, worth some $4.1B and a business partner of both Abramovich and Len Blavatnik, is barred from entering the U.S., per the Post. His assets were frozen by officials in 2018, but he bought 11 East 64th St. for $42.5B in 2008. He transferred ownership of those properties, as well as a property at 12 Gray St., to his relatives.

Alexei Kuzmichev, founder of Russia's largest private bank, Alfa Bank, which is currently sanctioned, is connected to 33 East 74th St., having paid $42M for the first four floors there in 2016, according to the Post. He also bought a three-bedroom unit in another building for $15.5M.

Len Blavatnik, one of the world’s richest men, is not on any sanction list and was included in the Post's roundup, although he is from Ukraine, not Russia, and has citizenship in Britain and the U.S. He previously told the Post he hasn't spoken to Putin since 2000. He, too, has amassed several multimillion-dollar properties in the city. He paid $31.25M for a townhouse at 2 East 63rd St. in 2005 and bought 15 East 64th St. for $51M in 2007. He also owns 834 Fifth Ave., for which he paid $80M in 2014, and 19 East 64th St., paying $90M in 2018.

The Post also highlighted fertilizer billionaire Dmitry Rybolovlev, who reportedly amassed his wealth thanks to Putin. He bought a 15 Central Park penthouse for $88M, which his spokesperson said was bought in trust for his daughter. In 2008, he paid $60M over the asking price when he bought a Palm Beach mansion from Donald Trump.

While Russia’s advance on Ukraine has sparked condemnation and sanctions from the West, it is not yet clear what impact it will have on some of the wealthiest Russians dealing in property in the U.S.

With the uncertainty and a decrease in the value of the ruble, many well-heeled Russians with means are very likely moving their holdings now, Daniel Gielchinsky, a Miami attorney and partner at DGIM Law, told Bisnow last week.

“In terms of the public outcry that we should take some sort of action, or somehow sanction the Russian oligarchs who have their fortunes here — there's no real mechanism to do it,” he said.

CORRECTION, MARCH. 1, 10:15 ET: Len Blavatnik was born in Ukraine, not Russia. An earlier version of this story did not make his country of birth clear.