Russian-installed officials in the eastern Ukrainian region of Luhansk on Friday accused Kyiv of firing missiles at an industrial complex in the region's main city, around 100 km (60 miles) behind the frontlines.

Videos posted on social media showed a large plume of thick black smoke billowing over Luhansk city from what authorities said was an industrial facility hit by two missiles fired by Ukraine.

Because the city lies far away from Ukrainian positions, the alleged strikes sparked speculation among analysts that Ukraine could have used a new missile with a longer range.

Leonid Pasechnik, the Russian-installed head of the region, which Russia proclaims as its territory, said the attack was carried out to disrupt the region's local Republic Day celebrations.

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Reuters was unable to verify the claims. There was no immediate official reaction from Kyiv to the claimed strikes.

Ukraine's Suspilne Donbas television station reported explosions in the city, quoting residents, who said the blasts occurred in a central district near a factory.

Russian-installed authorities said early information showed there were no civilian casualties and they were investigating which type of weapon was used in the strike.

The city of Luhansk is deep in eastern Ukraine, around 30 kilometres (18 miles) from the border with Russia and 100 kilometres (60 miles) from the frontlines of fighting.

That puts it beyond the reach of most of the shorter-range missiles, such as the U.S.-supplied HIMARS, that Ukraine has largely been using in the conflict so far.

Britain this week said it had delivered to Ukraine multiple longer-range cruise missiles, which can hit targets at 300 kilometres - the longest rockets that have been supplied to Ukraine by its Western partners.

The United States earlier this year said it would start providing Ground Launched Small Diameter Bombs (GLSDB), GPS-guided "smart bombs" to Ukraine which have a range of around 150 kilometres.