NATO Secretary General Jens Stoltenberg. Photo: EPA

While NATO allies help Ukraine with how to carry out their combat operations, it is the Ukrainians who need to make decisions on the battlefield, the Alliance’s secretary general, Jens Stoltenberg, told CNN in an interview.

Ukraine has been waging a counteroffensive operation focused on the southern regions as well as areas around the city of Bakhmut, in eastern Ukraine, and recently recaptured the strategically important settlement of Robotyne, in the Zaporizhzhia region.

"The Ukrainians are gradually gaining ground, meaning that they are pushing back the Russians. They are able to get through some of these heavily defended territories, not least minefields," Mr Stoltenberg told CNN’s Christiane Amanpour.

"And therefore, it is just even more important to support them. Because we all know that it’s fierce fighting, it’s a tough fight, and there is no easy way for victory for Ukrainians, but they are making achievements; they are gaining ground."

The Alliance’s top official said there is a constant dialogue going on between NATO members, who are delivering military support, training and advising, and Ukraine — but it is up to the Ukrainians to make "difficult and tough" decisions on the battlefield.

"What we have seen is that the Ukrainians have exceeded expectations again and again," Mr Stoltenberg stressed.

"We have to remember where the whole thing started last year with the full-fledged invasion by Russia [of] Ukraine. Then experts believed that Ukraine would last only a few days or a few weeks.

"Now they liberated the north around Kyiv, the east around Khakriv, and also territory in the south around Kherson. And now they are making even more gains.

"So we need to trust them. We advise, we help, we support. But at the end of the day this is the Ukrainian that has to make those decisions."