The European Union formally adopted broad economic sanctions against Russia on Thursday, aiming to make it pay a price over the Ukraine crisis in the hope Moscow will reverse course.
They were published in the EU's Official Journal later in the day, meaning that they come into effect on Friday.
The new measures, finally agreed earlier this week after months of hesitation, target Russia's banking, defence and energy sectors in view of its "actions destabilising the situation in eastern Ukraine," a statement said.
A first step limits access by Russian state-owned banks to Europe's financial markets, chief among them London, which will increase their cost of doing business and hinder their contribution to the economy.
Five banks were named, among them the largest in Russia: Sberbank, VTB, Gazprombank, VEB and Rosselkhozbank.
EU nationals and companies will no longer be allowed to buy or sell new bonds, stocks or other debt instruments with a maturity of more than 90 days issued by such banks, the statement said.
Sales of arms and dual-use technology are banned, along with sensitive technologies in the oil sector but not gas, where Russia supplies about a third of the EU's needs.
Analysts say the oil sector ban could really hurt over time because Russia relies heavily on advanced Western drilling technology, especially for the development of new fields in extreme environments such as the Arctic.
"The measures will apply to new contracts," the statement said, meaning current deals and activities are not covered.