Ukrainian leader Oleksandr Turchynov yesterday accused Russia of working to overthrow legitimate state power in Ukraine after pro-Russian rebels declared a resounding victory in referendums on self-rule in eastern regions.
Turchynov said the Kremlin was trying to disrupt a presidential election later this month which is taking centre stage in a confrontation pitting Moscow and the separatists against the government in Kiev and its Western backers.
RIA news agency quoted a rebel leader as saying the eastern Luhansk region would boycott the May 25 election. What he called the "Republic of Luhansk" may hold a further referendum on union with Russia, as Ukraine's Crimea region did under Russian military occupation before its annexation by Moscow in March.
Watch: Eastern Ukraine rebels see Russian future after referendum
Ukraine's election is intended to secure democratic continuity and legitimacy after pro-Moscow president Viktor Yanukovych fled the country in February, and Western governments have threatened more sanctions in the vital areas of energy, financial services and engineering if Moscow disrupts the vote.
Moscow said it respected the outcome of Sunday's referendums, in which separatists claimed 90 per cent support in the industrial Donetsk region while RIA, a Russian state news agency, reported 96.2 per cent backing in Luhansk region.
The results should be implemented peacefully, Russia said, without saying what further action it might take.
Eastern Ukraine has been plagued by turmoil as Kiev has tried to regain control of the largely Russian-speaking areas, and health authorities said 49 people had been killed in violence in the region of Donetsk since March 13.
The European Union declared the referendums illegal and increased pressure on Russia yesterday by taking a first step towards extending sanctions to companies, as well as people, linked to Crimea's annexation.
It added two companies and 13 people to the sanctions list.
However, revealing cracks in the West's united front, diplomatic sources said France would press ahead with a €1.2 billion euro (HK$12.8 billion) contract to sell helicopter carrier ships to Russia because cancelling the deal would do more damage to Paris than to Moscow.
The rebels have given differing accounts of their plans. However, one spokesman said these did not include taking part in electing a replacement for Turchynov, who has been acting president since pro-EU protesters forced Yanukovych out.
"As of today, we are now the Republic of Luhansk, which believes it to be inappropriate and perhaps even stupid to hold a presidential election," RIA cited the spokesman as saying.
"This land was never Ukraine ... we speak Russian," said Vyacheslav Ponomaryov, rebel mayor of the separatist stronghold of Slavyansk, threatening to kick out the Ukrainian army.
Moscow denies any ambitions to absorb the mainly Russian-speaking east, an industrial hub. However, it has massed troops on the Ukrainian border and Kiev fears they may be called in as peacekeepers.
Ukrainian Interior Minister Arsen Avakov said rebels had made a new attempt overnight to seize a television tower on the edge of Slavyansk.
"The information war that they are waging against us in the Donbass [east] is more dangerous than a bullet. We must answer back ... the enemy fears this more than special forces," he wrote on Facebook.
Russian President Vladimir Putin, who is in Sochi, did not comment personally, but the Kremlin released a statement on the referendum.
"We condemn the use of force, including of heavy weapons against civilians ... in Moscow, we respect the will of the people of the Donetsk and Luhansk regions and are counting on practical implementation of the outcome of the referendum in a civilised manner, without any repeat of violence and through dialogue," it said.