SLAVYANSK, Berlin - Russia on Tuesday rejected a new peace initiative for Ukraine as fears of open war mounted over the ex-Soviet republic, whose troops are waging an increasingly deadly offensive against pro-Moscow rebels.

‘Chaos and the risk of civil war’ are looming, French President Francois Hollande warned after Kiev announced the death toll from an assault on a rebel-held flashpoint town in the east had climbed over 34. ‘We are not very far from a military confrontation in Ukraine,’ added German Foreign Minister Frank-Walter Steinmeier in an interview to European newspapers.

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. On Tuesday, the Swiss presidency chairing the Organisation for Security and Cooperation in Europe urged a suspension of hostilities for that election to take place.

‘We need a ceasefire for the election,’ Swiss President Didier Burkhalter said. Ukraine’s foreign minister, Andriy Deshchytsia, appealed to 30 of his counterparts assembled in Vienna to help ‘eliminate the external threats and provocations supported by Russia’ to ensure the election goes ahead.

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 it ‘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 declared dead.

But he has kept an estimated 40,000 troops on the border for the past two months. And the Kremlin claims to be receiving ‘thousands’ of calls for help from eastern Ukraine. The US general commanding NATO’s military operations, Philip Breedlove, said Russian special forces the West believes are deployed covertly ‘may be able to accomplish his (Putin’s) objectives in eastern Ukraine’ without the need to invade.

NATO’s top military commander said he did not think Russian troops would enter eastern Ukraine, predicting that Moscow could achieve its goals through other means. General Philip Breedlove also told an audience in Ottawa that it was too early to say whether Russian special forces were firing missiles at Ukrainian helicopters. At least three helicopters have been shot down in the last week.

Ukraine is close to war, German Foreign Minister Frank-Walter Steinmeier warned in interviews published in four European newspapers on Tuesday.

Dozens of people died in the Ukrainian city of Odessa last week when pro-Russian militants clashed with their opponents, and Kiev forces are fighting separatists who have seized control of towns in the east of the country.

‘The bloody pictures from Odessa have shown us that we are just a few steps away from a military confrontation,’ Steinmeier told El Pais, Le Monde, La Repubblica and Gazeta Wyborcza. He added that the conflict had taken on an intensity ‘that a short time ago we would not have considered possible’.

Steinmeier’s ministry also warned Germans on Tuesday against travelling to Crimea, which Russia annexed from Ukraine in March, and reiterated an earlier advisory to avoid eastern areas.

‘It is urgently advised to avoid travelling to Crimea,’ the Foreign Ministry wrote on its website. ‘In the German government’s view, Crimea belongs to Ukraine but in actuality it is controlled by Russia. Due to the current situation German citizens can no longer be guaranteed consular services.’

The ministry added that it was advising against any travelling to eastern and southern Ukraine. It also urged German citizens to leave those regions and said journalists were particularly endangered.

An AFP reporter inside Slavyansk said the rebels were reinforcing defences around a security services building they occupy. He also said basic foodstuffs and other items were running increasingly short. Locals hostile to Kiev’s government have strewn tree trunks and tyres across the streets to slow any army advance. Separately on Tuesday, all flights in and out of Donetsk - a regional industrial hub of more than one million people - were suspended for hours, according to airport authorities, who gave no reason for the day-long closure.

Russia says the insurgency in Ukraine is a spontaneous rejection of the Kiev government that came to power in February, after street protests forced out the pro-Kremlin president. Russian state media, seen in east Ukraine, constantly refer to the new administration as being run by ‘fascists’ who embrace a Nazi-style ideology. That propaganda will likely become even more shrill on Friday, when Ukraine - like Russia - observes a holiday commemorating the Soviet victory over wartime Germany.

Putin, according to Russian reports, could make a triumphant visit to annexed Crimea on that day, after overseeing a parade of Russian military might on the Red Square in Moscow. German Chancellor Angela Merkel, Europe’s pointwoman in dealing with Putin over the crisis, said such a trip by the Russian leader would be a ‘pity’. Relations between the West and Russia are already plumbing depths not seen since the Cold War, when Putin was stationed as a KGB officer in the German city of Dresden.

The United States and the European Union are already exerting some sanctions pressure on targeted individuals and firms in Russia. Washington says they will be expanded to punishment of whole sectors of Russia’s slowing economy if Ukraine’s May 25 presidential election is prevented from taking place. That threat, on the back of Ukraine’s rising violence, sent stocks lower on Tuesday.

‘The situation in Ukraine looks set to be something that will continue to influence financial markets for a considerable amount of time,’ said a London-based broker, Jonathan Sudaria of Capital Spreads. Michael Clarke, head of the Royal United Services Institute, a security think-tank, said the situation was likely to deteriorate in the run-up to the elections. ‘We’re entering into a very dangerous period and I don’t think Putin is in full control of the forces he has unleashed,’ he told AFP.