Jens Stoltenberg, the Secretary-General of the North Atlantic Treaty Organisation (NATO), believes that the Ukrainian forces' advance into the occupied territories in eastern and southern Ukraine, which are under Russian occupation, has shown initial signs of success.

As Stoltenberg stated in an interview with USA Today, Ukrainian soldiers are gradually "gaining ground" by retaking seven small towns and villages from Russian troops. However, he cautioned against expecting quick and significant achievements.

"We need to be prepared that this offensive will be bloody and difficult," Stoltenberg said. "The Russians have had time to build — they're quite heavy defensive lines, and to breach them is a demanding task."

Stoltenberg noted that Russian troops have been poorly led, equipped and supplied.

"But what we have seen is that Ukrainians have the courage, the determination to liberate land...and push back the Russians," added the Secretary-General.

Earlier, French President Emmanuel Macron stated that Ukraine's counteroffensive had been ongoing for several days and should lead to conditions that would allow Kyiv to start negotiations on the most favourable terms.

The White House also confirmed the start of Ukraine's counteroffensive operations, leading to preparations for new military assistance in Washington.