Germany and France plan to impose additional sanctions on Russia, if the Ukraine's presidential election scheduled on 25 May is stopped, following Russian President Vladimir Putin's recent visit to the annexed Crimea peninsula.
Following talks with French President Francois Hollande in Stralsund, German Chancellor Angela Merkel said Putin must send more de-escalation orders for smooth presidential elections in Ukraine.
"We've had first signs, but these have to get stronger so eastern and southern Ukraine also get the message that everyone wants free and general presidential elections," Merkel said.
In a joint statement, Hollande and Merkel said: "If the internationally recognised presidential elections do not take place on May 25, this would destabilise the country further. France and Germany believe that in this case, appropriate consequences should be drawn."
Meanwhile, a source was reported by the Bild am Sonntag newspaper as saying that about 400 elite soldiers from Academi (formerly Blackwater) have been deployed to assist in the Ukrainian military operations against anti-government protesters in South Eastern regions of the country.
Nato estimated that some 40,000 Russian troops were near the border, although Moscow announced the forces have been drawn back.
The European Union (EU) and the US previously agreed to impose further sanctions on officials and companies associated with Russian President Vladimir Putin.