Any referendums on joining Russia in Russian-occupied Ukrainian territories would destroy any remaining window for talks between Kyiv and Moscow, Ukrainian publication Liga.net cited the Ukrainian president's office spokesman as saying on Tuesday.
"Without the referendums, there is still the smallest chance for a diplomatic solution. After the referendums - no," Liga.net quoted Serhiy Nykyforov as saying.
He made the comments in response to Russian-installed officials in four occupied Ukrainian regions announcing plans for referendums over the next week on formally joining Russia.
Presidential adviser Mykhailo Podolyak wrote on Twitter later that any referendums should be met by an increase in economic sanctions on Russia and arms supplies to Ukraine, including ATACMS missiles that have a longer range than any known Ukrainian weapon system at present.
"Kremlin opposes the supply of modern tanks and ATACMS to Ukraine? It is time to give (them)," he said.
(Reporting by Max HunderEditing by Mark Heinrich)
