"I can't offer you any guarantees," the EU's top diplomat Kaja Kallas told the Kyiv Independent when asked if she can offer any guarantee that the price cap on Russian oil will not lapse on July 15.

The EU Council will consider a sanctions list of 250 Russian individuals and companies on 13 July; the 21st sanctions package is still being negotiated.

"Every time we make a sanctions pact, it gets a little harder," said Danish Foreign Minister Lars Lokke Rasmussen.