The top US intelligence officer says fighting in Ukraine will likely wane through the winter as Russian and Ukrainian forces prepare for counterattacks in the spring.

Director of National Intelligence Avril Haines said on Saturday that most of the fighting is currently taking place around Bakhmut and other parts of the eastern region of Donetsk. Bakhmut is one of Ukraine's strongholds in the region.

She said the hostilities have "slowed down" after Russian forces withdrew from western areas of the Kherson region in November, and moved to the eastern side of the Dnipro River.

Haines said "we're seeing a kind of a reduced tempo already of the conflict...and we expect that's likely to be what we see in the coming months."

She said "the sort of question is, what will the counteroffensive look like potentially in the spring, in effect in March and in that area?"

Haines said "we expect that, frankly, both militaries are going to be in a situation where they're going to be looking to try to refit, resupply, in a sense reconstitute so that they're kind of prepared for that counteroffensive."

Regarding the view that Russia is seriously short of weapons, Haines said Russia is "not capable of indigenously producing" what it is expending at this stage. She said "we've indicated that their precision munitions are running out much faster in many respects."

Haines said Russia has "a lot of stockpiles." She added, "How viable those stockpiles are, how much they have, what they can use in different conflicts are obviously all questions that we look at quite carefully with our allies and partners."