UK Foreign Secretary William Hague has said that the "self-rule" referendums held in eastern Ukraine on May 11 have "zero credibility" in the eyes of the world.

"These votes, these attempts at referendums, have zero credibility in the eyes of the world. They are illegal by anybody's standards, they don't meet any standard, not a single standard of objectivity, transparency, fairness or being properly conducted as a public referendum or election and indeed the people organizing them didn't even pretend to meet any of those standards. The important thing is that the Ukrainian elections go ahead on the 25th of May," he said arriving at a EU foreign ministers meeting in Brussels on Monday.

"I think it is very important for us to demonstrate that we are ready for that third tier of sanctions, for more far reaching sanctions, depending on Russia's attitude towards the elections on the 25th of May," Hague said, adding that now this was most important thing of all.