EU chief Ursula von der Leyen on Wednesday said the EU would impose a gradual Russian oil ban, as Brussels unveiled new sanctions to punish Russia for invading Ukraine.

"We will make sure that we phase out Russian oil in an orderly fashion," the EU chief told a session of the European Parliament in Strasbourg.

"This is why we will phase out Russian supply of crude oil within six months and refined products by the end of the year," she added.

In a document seen by AFP, von der Leyen's proposal asked that Hungary and Slovakia, both hugely dependent on Russian oil, be given more time to meet the ban. 

Ambassadors from the 27 European Union countries will meet on Wednesday to assess her plan, and it will need unanimous approval before going into effect.

Von der Leyen also said the EU would ask that the member states agree to deny Sberbank, Russia's biggest bank, access to SWIFT, the global banking communications system.

By hitting Sberbank and two other banks, "we hit banks that are systemically critical to the Russian financial system and Putin's ability to wage destruction," she said.

The draft of her proposal also said the EU was seeking to add the head of the Russian Orthodox Church, Patriarch Kirill, to the latest list of sanctioned individuals in the package.

The new list includes 58 people, including many Russian military personnel, but also the wife, daughter and son of Kremlin spokesman Dmitry Peskov.

Von der Leyen said the list would add high-ranking military officers and other individuals "who committed war crimes in Bucha and who are responsible for the inhuman siege of the city of Mariupol".

"This sends another important signal to all perpetrators of the Kremlin’s war: We know who you are, and you will be held accountable," von der Leyen said.