The Secretary of the National Security and Defence Council, Oleksandr Turchynov, said he believed there is a real threat of a full-scale military invasion of Russia.
"The threat is real. In addition to occupying troops in Crimea and Donbas we see the concentration of [Russian] troops along the border with Ukraine," Turchynov told a press conference on 5 August.
He noted that Russia has begun formation of a combined tank army near Ukrainian borders. However, in his opinion, the Russian Federation is more likely to focus on "hybrid" war aimed at destabilization of the situation in Ukraine.
Turchynov says Russia's aerospace forces (VKS) are its most dangerous weapon.
"The first and most dangerous scenario is military, a full-scale military aggression, which is so far the most problematic and dangerous for the Kremlin itself," Turchynov said.
"The second scenario is the so-called hybrid one, which is most probable for today."
The 'hybrid' scenario, according to Turchynov, includes local military attacks against Ukrainian positions in Donbas and subversive activities across the Ukraine's territory.
Turchynov said Ukraine should give an adequate response in the case of aggravation of the situation, emphasizing that martial law cannot be introduced at the request of politicians in certain periods, and can be announced only in the case of danger to the state.
Earlier, Turchynov said NSDC might consider the introduction of martial law in the event of an aggravation of the situation in Donbas.