U.S. Deputy Treasury Secretary Wally Adeyemo sent the letter to the TUSIAD business association, which has some 45,000 members. Turkey's finance minister Nureddin Nebati called any concerns stemming from it "meaningless" on Friday.
NATO member Ankara opposes Western sanctions on Moscow and has ramped up trade and tourism with Russia even as it opposes the invasion. It has also pledged that the sanctions will not be circumvented in Turkey.
Some Turkish firms have purchased or sought to buy Russian assets from Western partners pulling back due to the sanctions, while others maintain large assets in the country. Here is a partial list:
TURKISH COMPANIES THAT ACQUIRED OR SOUGHT TO BUY RUSSIAN ASSETS SINCE WAR BEGAN:
* Belgian brewer Anheuser-Busch InBev said in April it was in active talks to sell its non-controlling stake in its Russian joint venture AB InBev Efes to Turkish partner Anadolu Efes.
* Turkey's Koc Holding's appliances giant Arcelik signed a share purchase agreement with U.S.-based Whirlpool for all shares in the latter's Russian units Indesit International JSC and Whirlpool RUS LLC for $233 million.
* Turkey's Fiba Retail is in talks to become a franchise partner for Spanish chain Mango's Russia stores, Russian media reported.
* Turkey's Flo Shoes reported in May that it was in talks to buy more than 100 stores owned by fitness brand Reebok in Russia.
TOP ISTANBUL-LISTED COMPANIES MAINTAINING RUSSIAN ASSETS BASED ON DISCLOSURES:
* Glass and glass products producer Sisecam holds four Russian subsidiaries with 31.88 billion roubles ($530.4 million) in assets. The company reported its annual production capacity in Russia to be 1.6 million tons at the end of 2021.
* Conglomerate Zorlu's appliances business Vestel has Russian assets valued at 8.81 billion roubles. With its sales and operational businesses, Vestel's Russian assets total 9.30 billion roubles.
* Is Bank's Russian subsidiary is valued at 4.76 billion roubles.
* Conglomerate Koc Holding's Arcelik has full ownership of Russian unit Beko LLC which has 4.28 billion roubles in assets.
* Construction mogul Enka's Russian subsidiary totals 3.85 billion roubles in assets.
* Denizbank's Russian subsidiary has 1.13 billion roubles in assets.
($1 = 60.1 roubles)
(Reporting by Azra Ceylan, Canan Sevgili and Halilcan Soran; Additional reporting by Elena Vardon; Editing by Jonathan Spicer and Jacqueline Wong)