Donetsk, Reuters—Pro-Russian separatists in eastern Ukraine staged swearing in ceremonies for their leaders on Tuesday after votes dismissed as a farce by Kiev, which says they violated terms of a peace plan to end a war that has killed more than 4,000 people.

NATO’s highest ranking officer, a US general, said conditions were now in place to create a “frozen conflict,” a term the West uses to describe rebel regions carved out of other ex-Soviet states that Moscow protects with its troops.

The inauguration ceremonies in east Ukraine took place even as tens of thousands of people marched in Moscow for “Unity Day,” a nationalist holiday celebrating a 17th century battle, revived under President Vladimir Putin to replace the Soviet-era celebration of the Bolshevik revolution. Ukraine featured heavily in speeches for the occasion.

Most fighting has halted in the war in eastern Ukraine since September, when Kiev agreed to a truce after its forces were pushed back by what it and Western countries say was an incursion by armored columns of Russian troops.

But the frontline remains dangerous and tense, with both sides complaining of shooting nearly every day. Artillery from the direction of the wreckage of Donetsk’s international airport, still under government control, thudded during the rebel leader’s inauguration in the city.

Ukraine’s President Petro Poroshenko has ruled out resuming the military campaign to recapture the rebel-held regions but has called a meeting of security chiefs for later on Tuesday.

Kiev’s military spokesman said there had been more shooting incidents recently and Russia was building up its forces in rebel held territory. Moscow officially denies its troops operate in eastern Ukraine although many have died there.

Moscow says the election of Alexander Zakharchenko and Igor Plotnitsky as leaders of the Donetsk and Luhansk “people’s republics,” which jointly call themselves “new Russia,” means that Kiev should now negotiate with them directly.

Kiev has always rejected this, describing the rebels as Russian-backed “terrorists” or “bandits,” with no legitimacy.

The worry for the West is that Moscow, which has already annexed Ukraine’s Crimea peninsula, will now also exert control over eastern Ukraine’s industrial Donbass region in perpetuity, as it has done for two decades in parts of Moldova and Georgia that broke away when the Soviet Union collapsed.

“I’m concerned that the conditions are there that could create  a frozen conflict,” said US Air Force General Philip Breedlove, the highest-ranking NATO officer, said in Washington.

Russia’s border with east Ukraine had softened to the point of becoming completely porous, while the line inside Ukraine between government and rebel territory had hardened, he said.

In Donetsk, an industrial city which had a million people before the war, 38-year-old former coal mine electrician Zakharchenko was sworn in as head of the self-proclaimed “Donetsk People’s Republic.”

One of the few top guerrilla commanders in eastern Ukraine who comes from Donetsk rather than Russia, Zakharchenko has led the separatists since August when he took over from a Russian. He was elected on Sunday, along with Plotnitsky in neighboring Luhansk, in votes that Kiev and the West denounced as illegal.

At Tuesday’s ceremony in a Donetsk drama theater, Zakharchenko swore to “honestly serve the interests of the people of the Donetsk People’s Republic.”

Balloons floated onto the stage while Cossacks in scarlet and black uniforms and dancers in traditional peasant garb shared the theater with Zakharchenko’s honor guard of heavily-armed fighters, some with Russian flag patches on their arms.

A Russian parliamentarian, Alexei Zhuravlyov, told the audience the elections “were democratic and clean which many countries could envy, including Western ones.”

Before the ceremony, another separatist figure, Andrei Purgin, said: “We are starting history with this inauguration and what happens today will be repeated. We are laying down the traditions of the Republic.”

Putin has pressed on with Russia’s campaign in Ukraine despite US and European economic sanctions.

“Dear friends, this year we have had to face difficult challenges. And as has happened more than once in our history, our people responded by consolidating and with a moral and spiritual upsurge,” Putin told a Unity Day gala, alluding to the conflict without mentioning sanctions or Ukraine directly.

“The desire for justice, for truth has always been honoured in Russia. And threats will not force us to abandon our values and ideals.”

At an open air concert in Moscow following the parade, politicians called on Putin to recognise the results of the rebel elections. Putin has yet to do so, although Moscow said it would before the votes were held.

Since a ceasefire was agreed in September as part of what is known as the Minsk agreements, which Russia signed along with Ukraine and rebel leaders, Putin appears to have set course for a long-term solution that will leave the Donbass internationally recognized as part of Ukraine but beyond Kiev’s control.

Russia has used such tactics to hobble the aspirations for Western integration of Moldova and Georgia, where breakaway enclaves have enjoyed Russian protection since the early 1990s.

When Georgia tried to retake a separatist enclave in 2008, Moscow swiftly invaded to protect it. An official from that region, South Ossetia, spoke at Zakharchenko’s inauguration.

In recent weeks, Russia and Ukraine reached an interim agreement on gas supplies, allowing them to resume the most important part of their economic relations and make the status quo more stable, without resolving the separatist conflict.

But Kiev still has wider ambitions for improved trade ties with the West, including eventual membership in the EU, which will be harder to achieve as long as nearly 10 percent of its population and a larger slice of its industrial output is in territory controlled by armed men who profess loyalty to Russia.

The rebels in eastern Ukraine rose up in April after Moscow seized the Crimea peninsula following the overthrow of a pro-Russian president in Kiev. More than 4,000 people have been killed in months of fighting since, including 298 aboard a Malaysian airliner shot down over rebel territory in July.

From June through August Ukrainian forces were on the offensive, but the momentum rapidly swung back after what the West says was a ground assault by the Russian military to rescue the rebels from defeat and force Kiev to agree a ceasefire.

Kiev says the Minsk agreements provided only for the election of local officials in the east under Ukrainian law, and not for separatist ballots to install leaders of breakaway entities who seek close association or even union with Russia.

After an election in Ukraine on October 26 that saw parties sympathetic to Moscow all but wiped out, Poroshenko is now fully supported by a pro-Western power structure that is determined to stop the break-up of the country. He may come under pressure to take a firmer line.

Calling for “adjustments” to be made in the way Ukraine handled the east, Poroshenko said he plans to scrap a law offering “special status” to eastern regions, and would discuss it at Tuesday’s meeting. The law envisages letting the Donetsk and Luhansk regions run their own affairs and would shield separatist fighters from prosecution.

For now, a resumption of all-out war seems unlikely. But a Kiev military spokesman said Poroshenko’s meeting of Ukraine’s National Security and Defence Council on Tuesday would consider the situation in the Donbas region “militarily”. Andriy Lysenko said there had been shooting near Mariupol south of Donetsk.

“A build-up of Russian military capability has been detected in regions controlled by the terrorists,” Lysenko said.

In a joint statement, the two rebel leaders Zakharchenko and Plotnitsky said the people of the Donbas were determined to “defend their freedom and their right to a peaceful and dignified life”.