The sanctions, which for the first time targeted Russia's Sberbank, were timed to coincide with new European Union economic penalties that included restrictions on financing for some Russian state-owned companies and asset freezes on leading Russian politicians.

The U.S. Treasury Department said the sanctions include a ban on U.S. individuals or companies dealing with Rostec, a major Russian technology and defense conglomerate, in debt transactions of more than 30 days maturity.

Assets also were blocked for five state-owned defense technology firms: OAO Dolgoprudny Research Production Enterprise, Mytishchinski Mashinostroitelny Zavod OAO, Kalinin Machine Plant JSC, Almaz-Antey GSKB and JSC NIIP.

Oil industry sanctions will affect exploration and production of Russian deepwater, Arctic offshore and shale projects by five Russian energy companies: Gazprom, Gazprom Neft, Lukoil, Surgutneftegas and Rosneft, the Treasury said.

The new U.S. sanctions tighten the financial noose on six Russian banks, including Sberbank, Russia's largest by assets, by barring U.S. individuals and companies from dealing in any debt they issue of longer than 30 days maturity.

The five banks previously covered had only faced a restriction on debt maturities of more than 90 days. Like those five, Sberbank now also faces a ban on U.S. equity financing.

The Treasury Department also imposed sanctions prohibiting U.S. individuals and companies from dealing in new debt of greater than 90 days maturity issued by Russian energy companies Gazprom Neft and Transneft.

"These steps underscore the continued resolve of the international community against Russia's aggression," U.S. Treasury Secretary Jack Lew said in a statement. "Russia's economic and diplomatic isolation will continue to grow as long as its actions do not live up to its words."