The second package of EU sanctions would affect 70 percent of the Russian banking services market and key state-owned companies, including defense entrepreneurs, European Commission President Ursula von der Leyen said on Twitter, on Friday.

The bloc's leaders agreed in principle at an emergency overnight summit to impose new economic sanctions, joining the United States and others in taking steps such as curbing Russia's access to technologies.

The EU will freeze Russian assets in the bloc and halt its banks' access to European financial markets as part of what EU foreign policy chief Josep Borrell described as "the harshest package of sanctions we have ever implemented".

Von der Leyen also said that the sanctions target the energy sector, a key economic area which especially benefits the Russian state, and the bloc's export curbs to Russia will hit the oil sector by making it impossible for Russia to upgrade its refineries. 

French President Emmanuel said the war showed Europe needed to become a real power and be independent in the fields of energy and security.

British Prime Minister Boris Johnson said he would aim to cut Russia off from the U.K.'s financial markets as he announced a new set of sanctions in response to Russia's ongoing military operations in Ukraine.

(With input from Reuters)