"We are proud that during the special military operation our fighters act with courage, professionalism, like real heroes," Putin said in televised remarks during a Kremlin meeting with military academy graduates.

Referring to Western sanctions imposed on Russia over the intervention in Ukraine, he said "they will be overcome".

And "in the face of new threats and risks, we will further develop and strengthen our armed forces", he said, promising the new Sarmat intercontinental ballistic missile would be commissioned by the end of the year.

"There is no doubt that we will be even stronger," Putin added.

On February 24, Putin sent troops into neighbouring pro-Western Ukraine to "de-militarise" and "de-nazify" the country.

Putin has repeatedly claimed Russia's economy has managed to weather the barrage of unprecedented international sanctions.