Russia rejected a new peace initiative for Ukraine as fears of open war mounted in the ex-Soviet republic, whose troops are waging a deadly offensive against pro-Moscow rebels.
French President Francois Hollande and German Foreign Minister Frank-Walter Steinmeier added their voices to the chorus warning that skirmishing in the east of the country could trigger a civil war.
Underlining the risk, Kiev announced that the death toll from an assault on a rebel-held flashpoint town had climbed to more than 34.
The West, which is threatening to broaden sanctions on Russia over the worsening crisis, sees a May 25 presidential poll in Ukraine as crucial to hauling the country back from the brink.
Yesterday, the Swiss presidency -- which chairs the Organisation for Security and Cooperation in Europe -- urged a suspension of hostilities for that election to take place.
Ukraine's foreign minister Andriy Deshchytsia urged 30 of his counterparts assembled in Vienna to help "eliminate the external threats and provocations supported by Russia."
But Russian Foreign Minister Sergei Lavrov, also at the Vienna meeting of the Council of Europe, said holding the vote during the current violence would be "unusual".
President Vladimir Putin's spokesman has been more blunt, calling the idea "absurd".
Lavrov also dismissed a European push spearheaded by Germany to hold fresh peace talks on Ukraine after the collapse of an April 17 agreement that Moscow has already declared dead.
Any talks excluding the pro-Russian rebels active in Ukraine's east and southeast "would hardly add anything," he said.
The diplomatic impasse came as bloodshed soared in Ukraine.
Nearly 90 people have died in less than a week: half around the eastern town of Slavyansk, held by rebels since early April; and half in the southern port city of Odessa, where clashes culminated in a deadly inferno last Friday.
Most of those killed have been pro-Russian fighters and activists.
