The European Union's forthcoming sanctions on Russia will target banks, in particular Sberbank, as well as oil, European Commission President Ursula von der Leyen told German newspaper Bild.

Bild am Sonntag, in an interview published on Sunday, asked her to name the key points of a planned sixth round of sanctions.

"We are looking further at the banking sector, especially Sberbank, which accounts for 37% of the Russian banking sector. And, of course, there are energy issues," she said.

She also said that the EU was working on "clever mechanisms" so that oil could also be included in the next sanctions.

"What should not happen is that (Russian President Vladimir) Putin collects even higher prices on other markets for supplies that would otherwise go to the EU," she was quoted as saying.

"The top priority is to shrink Putin's revenues," she said.