The new list took aim at a key unit of Bank Rossiya, often called the personal bank of Russian president Vladimir Putin, and some of Russia 's largest construction companies.
And it also blacklisted a large number of Russian companies operating in Crimea , including major maritime and defense businesses.
The sanctions aim to lock those blacklisted out of global financial networks, thereby limiting their ability to do business, by banning any US entities and individuals from doing business with them.
That would impact not only US banks but also the US branches of foreign banks, making it difficult for them to serve the sanctioned firms.
The US Treasury said the new move aims at countering efforts by Russian entities to circumvent existing sanctions on individuals and companies.