KIEV, May 8 -- Ukraine would continue its military operation in eastern regions regardless of whether pro-Russian protesters postpone their planned independence referendum on May 11, a Ukrainian security official said here Thursday.

"The anti-terror operation will continue regardless of any decisions of one or another subversive and terrorist group," Security and Defense Council Secretary Andriy Parubiy told reporters.

Describing the upcoming referendum on secession in eastern Ukraine as a "political fraud", Parubiy said the vote "has no future".

Parubiy voiced his hope the military operation to retake the cities and towns seized by pro-Russian activists in the country's crisis-hit regions will end "on a high note".

In early April, the protesters announced the creation of sovereign People's Republics of Donetsk and Lugansk and set a referendum for May 11 to validate the decision.

On Wednesday, Russian President Vladimir Putin appealed to the activists to postpone Sunday's vote and demonstrators said they would consider Putin's request.

The Ukrainian government launched its military operation against separatists on April 13.