“Such a vote could have no democratic legitimacy and would only further worsen the situation,” a spokeswoman for EU foreign policy Catherine Ashton said.

“Any such type of referendum is not something that we can support,” said Maja Kocijancic. “We believe that such referendums should not take place and we fully support Ukraine’s territorial integrity and sovereignty and independence.”

Rebel leaders in the self-styled Donetsk People’s Republic as well as the towns of Slavyansk and Lugansk said they would push ahead with the referendums Sunday despite a call by Russian President Vladimir Putin to delay them.

“We take good note of president Putin’s remarks,” Kocijancic said, describing them as “a step that could help de-escalation” but adding that the EU “will see whether words are followed by deeds”.

EU foreign ministers gather in Brussels on Monday, a day after the referendums, and could decide to impose more sanctions on Russians and Ukrainians held to be involved in fostering instability in the area.

Ambassadors from the 28 EU nations on Wednesday agreed in principle to expand the legal criteria for targeting people or entities over the crisis.

The EU so far has imposed asset freezes and visa bans against 48 Russians and Ukrainians for violating or threatening Ukraine’s territorial integrity. The new critera widens the potential circle by targeting those responsible for fostering instability or insecurity, diplomats said.