Kyiv claimed on Friday that an estimated 32 tanks had crossed over into the Ukrainian territory of Luhansk from Russia on Thursday.
Ukrainian military spokesperson Andriy Lysenko also said that the convoy consisted of 30 trucks filled with troops and heavy weapons, including 16 howitzer cannons.
Trucks and three mobile radar stations were also sighted, Lysenko said.
However, a report from Russia's Interfax news agency quickly denied the claims as a "provocation," citing a Russian defense ministry spokesperson.
Kyiv readies forces in east
Earlier this week, NATO reported Russian troop movements near the Ukrainian border. The announcement coincided with renewed tensions between Kyiv and separatists in eastern Ukraine who elected leaders for a self-declared "People's Republic of Donetsk" last weekend, despite international condemnation.
Kyiv responded to the ballot - which it deemed illegal under a peace agreement signed in September - by deploying more soldiers to several eastern Ukraine cities in a bid to repel any possible attacks by pro-Russian separatists.
Both Kyiv and Western leaders have been watching Moscow since earlier this year when Russian President Vladimir Putin dispatched soldiers into the autonomous Black Sea peninsula of Crimea.
That move followed the forced resignation of the pro-Kremlin Ukrainian leader, Viktor Yanukovych, who was unable to quell months of mass popular protests over his shelving of a proposed association agreement with the EU.
Crimea was annexed by the Russian Federation in March. Shortly thereafter, fighting broke out in eastern Ukraine where pro-Russian separatists vowed to free the region from Kyiv's influence, favoring instead closer ties with Russia.
The war in eastern Ukraine has claimed over 4,000 lives and has led to the worst phase in diplomatic relations between Russia and the West since the Cold War.
Despite Western assertions of clear evidence that Moscow has provided logistical and military support the separatists, Putin has repeatedly denied those claims.
kms/ipj (AFP, Reuters)