Pro-Russia separatists in eastern Ukraine hold controversial leadership elections on Sunday which Kiev and the west have refused to recognise and which threaten to deepen the international crisis over the conflict.

Fighting raged across the region on the eve of the vote, with seven Ukrainian fighters killed and intensive shelling at the ruins of Donetsk airport, a key battleground between the rebels and government forces.

The elections in the self-declared Donetsk People’s Republic and Lugansk People’s Republic, which are based around the two main rebel-held cities, are designed to bring a degree of legitimacy to the makeshift military regimes that already control them.

Both are choosing new presidents and parliaments, but there is little question that the current unelected rebel leaders – Aleksandr Zakharchenko in Donetsk and Igor Plotnitsky in Lugansk - will be confirmed in their posts.

No international election monitors will be present for the vote, and no minimum turnout has been set by the organisers, reflecting the uncertainty over how many voters will bother turning out.

“These elections are important because they will give legitimacy to our power and give us more distance from Kiev,” said Roman Lyagin, the election commission chief of the Donetsk People’s Republic.

Russia, which denies fomenting the rebellion but clearly maintains close links to the separatists, has stated it will recognise the election results.

That infuriated Ukraine’s pro-western president, Petro Poroshenko, who referred to “the pseudo-elections that terrorists and bandits want to organise on occupied territory”.

Moscow’s backing for the vote has sparked a new round of criticism from the west, which has said that punishing sanctions against the Russian economy will not be lifted until the Kremlin does more to help implement a repeatedly violated truce in Ukraine.

The war has claimed more than 4,000 lives since it broke out in April, with rebels wresting control of much of Ukraine’s industrial south-east.

The truce signed on 5 September, with Russia as one of the signatories, has stemmed the fighting but brought little sign of lasting peace. More than 300 people have died in the last 10 days alone, the UN said.

In a four-way telephone call on Friday, the leaders of Ukraine, Germany and France urged the Russian president, Vladimir Putin, not to recognise the polls.

The White House said: “We deplore the intent of separatists in parts of eastern Ukraine to hold illegitimate so-called local ‘elections’.”

The EU and the Nato military alliance have also condemned the polls.

Meanwhile, Ukraine’s national security service, the SBU, issued a warning late on Friday of the risk of “provocations” during the separatist votes.

“The process of voting itself and of taking part in these elections is dangerous,” an SBU official, Markiyan Lubkivsky, said. “Serious provocations are being prepared that can then be blamed on the Ukrainian authorities.”

More violence seemed certain, given a spate of heavy shelling across the conflict zone over the last week.

On Saturday, Ukrainian authorities announced the deaths of six soldiers in the last 24 hours. Another soldier was killed and three more wounded in shelling later in the day, officials said.

The rebels rarely give out casualty figures.

A Donetsk resident, Vera, 45, who was selling eggs in a small market, said she would vote “against the fascists” – an insult against Ukraine’s pro-western government that has become widespread in the separatist region and in Russia’s powerful state media machine.

However, Lyubov Georgiyevna, 75, a retired teacher, said: “I won’t vote. It won’t change anything.” She said above all she wished she could sleep at night without the sound of explosions.