Russia is bringing more troops on rotation and may attempt further advances on Ukrainian soil, Ukraine’s interior ministry adviser Vadym Denysenko said.
It comes days after Vladimir Putin’s regime claimed its invasion was going to plan and that it would only focus on the separatist-controlled Donbas region of eastern Ukraine in future.
But the West said the Kremlin’s assault has largely stalled in the face of Ukrainians’ fierce resistence.
Mr Denysenko also said in a televised address that Russia has started destroying Ukrainian fuel and food storage depots, meaning the government will have to move the stock in the near future.
Meanwhile, Putin’s regime is trying to “create a North and South Korea in Ukraine” after failing to takeover the whole country – according to Kyrylo Budanov, head of the Ukrainian millitary intelligence.
He added that Ukraine would soon launch guerrilla warfare in Russian-occupied territory.