NATO Secretary General Jens Stoltenberg has said he expects the Ukrainian Armed Forces to make progress in their fight against the Russian occupying forces, noting that it will be tough.

"We must be prepared for the long haul. Wars are unpredictable by their very nature. What we do know is that what happens at the negotiating table is inextricably linked to the situation on the battlefield," Stoltenberg said in an interview with dpa.

The NATO Secretary General believes that only with military support will Ukraine remain a sovereign and democratic state, and Russian President Vladimir Putin will see that he cannot prevail on the battlefield.

Commenting on an article by Valerii Zaluzhnyi, Commander-in-Chief of the Ukrainian Armed Forces, in which he stated that the war had reached a deadlock, Stoltenberg noted that it was always clear that the situation would be challenging.

"We knew that Russia had been preparing defensive lines for months – with mines, tank trenches, and a lot of defensive positions," he said.

However, Ukrainian forces "have managed to make progress and liberate more territory", Stoltenberg stressed.

Czech President Petr Pavel said the current situation on the battlefield does not indicate that Ukraine can gain a military advantage. The official believes time is in Russia's favour and that negotiations might start next year.

Valerii Zaluzhnyi, Commander-in-Chief of the Ukrainian Armed Forces, believes that the war with Russia is entering a new stage: "a positional" fight with static and exhausting battles. In order to achieve victory, high technologies are essential.