European Commission President Ursula von der Leyen said in Brussels on Monday that the EU has yet to agree on an oil embargo against Russia, and a deal on new sanctions against Russia is expected in the coming days, adding that all issues regarding the sanctions have been solved except the delivery of "crude oil via pipeline."

Estonian Prime Minister Kaja Kallas also said it was more realistic to expect an agreement next month. 

"I don't think we'll reach an agreement today. We'll try to reach an agreement by the summit in June, this is the realistic approach by now," Kallas said.

The next EU summit is scheduled for June 23-24.

Earlier Reuters reported that an eventual sixth package of EU sanctions will include a ban on seaborne oil imports, with pipeline oil supplied to landlocked Hungary, Slovakia and the Czech Republic to be sanctioned at some later point.

(With input from Reuters)