“I think that in the near future a referendum will be held on the territory of the republic, during which the people will … express their opinion on joining the Russian federation,” Russian news agencies quoted Leonid Pasechnik as saying.

“For some reason, I am sure this will be the case,” he said.

Russia launched its military action in Ukraine in late February, saying it was acting in defence of the self-proclaimed Donetsk and Lugansk republics in the country’s east.

President Vladimir Putin had days earlier recognised the two regions as independent.

The industrial, mainly Russian-speaking regions broke from Kyiv’s control in 2014 in fighting that over the next few years claimed more than 14,000 lives.

Russia that year annexed Crimea from Ukraine after a pro-Moscow leader was ousted in a popular uprising and a referendum was held in the southern region on becoming part of Russia.