In eastern Ukraine, the frozen conflict between Russian troops and Moscow-backed separatists and forces loyal to Kiev is about to thaw.

Pro-Russian separatists in the self-proclaimed breakaway Republics of Lugansk and Donetsk took to the polls on Sunday to vote in controversial elections to determine their leadership. The West has refused to recognize the results of these elections and has called on Moscow to do the same – calls which were met by massive flood of Russian bombers flying near NATO airspace in maneuvers some believe were designed to simulate a nuclear attack.

Russia, which supports the rebels but denies fighting on their side, says it will recognize the results of the elections. The United States and European capitals, which have imposed heavy economic sanctions on Russia, back Kiev in condemning the polls as illegal.

Both self-declared republics were choosing new presidents and parliaments, but there was little question that the current unelected rebel chiefs — Alexander Zakharchenko in Donetsk and Igor Plotnitsky in Lugansk — would be confirmed in their posts.

No international election monitors were present for the vote, and no minimum turnout has been set by the organizers, reflecting the uncertainty over how many voters could turn out.

Shortly after Ukrainian separatists began voting, reports began to flood social media which purported to show Russian troops crossing the Ukrainian border.

In Donetsk, the main rebel-held city in Ukraine’s industrial south-east, AFP reporters saw about 20 trucks, some carrying anti-aircraft guns, heading towards the government-held airport, although it was not clear whether these were new forces.

Several Western news outlets reported witnessing heavy movement of troops near Donetsk.

Among them, reporters for the news sites buzzfeed.com and mashable.com tweeted that they had seen a large military column. Buzzfeed’s Max Seddon wrote: “31 unmarked Kamazes (military trucks) just drove past towards Donetsk. Anti-aircraft weapons, ammunition boxes, radar systems, a bus of gunmen.”

Unverified videos posted to YouTube purportedly show columns of Russian soldiers streaming into eastern Ukraine’s cities.

A ceasefire which commenced on September 5 by both separatists and Ukrainian force froze the conflict in Ukraine in place, but the fighting never truly ended. As winter nears, fighting has again begun to flare.

“Despite the cease-fire in eastern Ukraine, acts of indiscriminate shelling and security incidents continue to put civilians at risk,” read a statement recently released by the International Red Cross. “The approaching winter makes the situation of both residents and displaced people even more difficult.”

“Six government soldiers were killed and 10 were wounded by rebel fire in the Donetsk and Lugansk regions in the past 24 hours,” Bloomberg reported on Saturday, citing Ukrainian military sources. “The United Nations estimates total deaths in the conflict at more than 4,000, with 1 million people displaced.”