NATO General Secretary Jens Stoltenberg said that Russia is "trying to regroup, resupply and reinforce" its offensive in eastern Ukraine's separatist Donbas region despite Moscow's claim that it would reduce military activity.

The NATO chief made the remark while releasing his Annual Report 2021 here on Thursday.

"We have heard the recent statements that Russia will scale down military operations around Kiev and in northern Ukraine. But Russia has repeatedly lied about its intentions," Stoltenberg said in a statement published on the NATO website.

"So we can only judge Russia on its actions, not on its words."

He went on to say that "according to our intelligence, Russian units are not withdrawing, but repositioning".

As Russia "maintains pressure on Kyiev and other cities... We can expect additional offensive actions, bringing even more suffering", the NATO chief added.

Stoltenberg further said that the Ukrainian forces are now "bigger, better-equipped, better-trained, and better-led than ever before".

"And they are putting their training and their equipment to use on the front lines, with courage that has inspired the world."

He once again reiterated that Russia "must end this senseless war. Withdraw all its troops. And engage in talks in good faith."

On a similar note, the UK's Ministry of Defence also claimed that "Russia is redeploying elements of its forces from Georgia to reinforce its invasion of Ukraine".

In its latest update late Thursday night, it said that "between 1,200 and 2,000 of these Russian troops are being reorganised into 3 x Battalion Tactical Groups".

"It is highly unlikely that Russian planned to generate reinforcements in this manner and it is indicative of the unexpected losses it has sustained during the invasion."