The Russian army is suffering huge losses in Ukraine, shows no sign it has improved its “meat grinder” tactics and is struggling to sustain a stuttering offensive that is “advancing, if at all, in metres not kilometres”, Britain’s defence secretary Ben Wallace said on Friday.

Despite fears that Russia is poised to launch a huge attack around the first anniversary of its full-scale invasion of Ukraine, Wallace said there was “no evidence of a big massing of Russian forces” akin to the assault on February 24 last year.

Speaking to the Financial Times on the sidelines of the Munich Security Conference, Wallace said the best Moscow had managed so far was a series of probing attacks along the frontline reinforced with recruits following a recent mass mobilisation. But he said those assaults had only led to high Russian casualties.

He added that Kyiv’s western allies were “more resolved than ever” to help Ukraine repel Russian forces and one clear sign was a strengthening of support from the US, which is now “committed to seeing the conflict through to the end”.

“There is no evidence to date of a great, big Russian offensive,” Wallace said. “What we have seen is an advance on all fronts, but at the expense of thousands of lives . . . We should actually question the assertion that they [the Russians] can go on.”

There has also been a shift in attitude about military aid among Kyiv’s western allies. This time last year, he said, they were debating whether to send anti-tank missiles to Kyiv. Now they are sending western main battle tanks.

“What has changed is that the US has decided to be more assertive,” Wallace said, pointing to the almost $8bn of military aid Washington has committed this year.

“Just think about it: we [western allies] have convened twice in the past three weeks [to discuss military aid], at the Ramstein [US air base in Germany] and at the Nato defence ministers meeting this week. That is a big change.”

One bridge that Kyiv’s allies have not yet crossed, however, is the provision of western fighter jets to Ukraine. President Volodymyr Zelenskyy made an eloquent plea for “wings for freedom” during an unexpected visit to London earlier this month.

But Wallace cautioned such supplies were still a long way off and that the modern fighter jet training the UK had offered to Ukrainian pilots was a “long-term resilience measure for after the war when Ukraine needs to defend itself”.

Wallace’s assessment of the state of the battlefield comes as Moscow’s full-scale invasion approaches its first anniversary next week. Since the start of the war, more than 180,000 Russian troops had been killed or wounded and, according to US estimates, two-thirds of the army’s tanks had been lost, he said.

Despite these losses, Wallace said there was no sign that the Russian army had changed its approach. He cited reports that 3,000 Russian soldiers had died during a three-day attack last week on the southern Ukrainian town of Vuhledar.

“Russian recruits are still being shoved into the meat grinder,” Wallace said. “And I am not sure that is sustainable, even for Russia, because 180,000 people have wives, mothers, sisters and friends and it becomes impossible for the scale of that loss to be hidden from the Russian people.”

Western officials also believe that Russia is struggling to source weapons and other materiel for its war effort. They cite the long gaps between its missile and drone attacks on Ukrainian infrastructure, and “active rationing” of shells for Russian artillery on the front line.

Kyiv’s western allies are similarly struggling to maintain supplies of artillery shells and other munitions and weaponry to Ukraine.

Wallace said that, while Ukraine might be suffering some shortages, this was a timing issue and Kyiv’s western backers had no strategic problem in continuing to supply Ukraine’s war effort.

“There’s always been a sense of shortages on [Ukraine’s] front line, but I don’t see any sign of strategic shortages . . . although there is a bit of a time lag” in getting supplies through, Wallace said.

The challenge, he added, was for Ukrainian forces to be precise in their use of weaponry and to continue fighting using western methods. “Do you need 100 artillery shells to blow up a Russian position, or just five? If you can be accurate, you don’t need 100 shells,” he said.

“Russia still has significant forces at its disposal,” Wallace said. “But what we have discovered is that when they muster them, they get whacked . . . They’re struggling.”