Russia says its economy is strong. It just fired a top economist who warned otherwise

Russian government officials told CNBC that the economy is strong and healthy despite "unprecedented foreign pressure" following the country's full-scale invasion of Ukraine in early 2022.

That message sits in stark contrast with the views of the former chief economist of Russia's state-controlled development bank VEB, who was dismissed on Sunday after comments he made earlier in the year were reported in Russian-language media.

Andrei Klepach, a former deputy economy minister, was reportedly fired after presenting a report warning that Russia could not win a prolonged war of attrition with Ukraine and predicting a major social crisis.

Klepach's dismissal was directly linked to his scathing economic assessment, according to exiled independent Russian outlet The Bell, which cited unnamed sources familiar with the matter when it first reported the news. CNBC could not independently verify the report.

"In this war of attrition, we will not win the competition. We're under the illusion that everything will collapse. It hasn't, and it won't. Our costs are mounting," Klepach said in a speech presented to fellow economists on May 21, according to a translation.

"I believe Russia won't collapse, but I'm almost certain that we'll end up in a social crisis. We won't collapse economically, but our lag will widen, with all the ensuing consequences," he added.

The move to dismiss Klepach appears to underscore the Kremlin's zero-tolerance approach to public criticism and opposition to its military campaign in Ukraine after nearly four-and-a-half years of war.

Russian government officials remain defiant over the country's economic situation.

The Russian embassy to the U.K. told CNBC that Russia's fiscal position remains "significantly stronger" than that of many Western economies, pointing to foreign public debt of around $57 billion — noting that this is "considerably less" than the amounts the U.S., U.K., Italy or France spend on debt servicing alone.

"The Russian economy remains resilient, as does the will of our people," a spokesperson for the Russian Embassy to the U.K. told CNBC by email.

"Attempts to undermine Russia through economic pressure have not produced the results their authors expected," they added.

"On the contrary, the West – including the UK – is itself paying a substantial price for its reckless sanctions policy. British businesses have lost access to the Russian market, while disrupted supply chains and higher energy and commodity costs have imposed additional costs on the U.K. economy.