With the US presidential elections looming, President Joe Biden called on Saturday Russian President Vladimir Putin a "brutal tyrant," vowing that the United States "will not walk away" from supporting Ukraine.

In a speech to graduates at the US Military Academy at West Point, Biden said that the United States continues to provide Ukraine with arms and military training.

His statement comes as Russian forces are making ground gains across the front line, especially in the Kharkiv region.

Read more: Biden disgraced himself, his country: Kremlin on slurs against Putin

Biden claimed that there were "no American soldiers in the war in Ukraine" and that he is "determined to keep it that way."

"But we are standing strong with Ukraine and we will stand with them. We're standing against a man whom I've known well for many years, a brutal tyrant. We may not, we will not walk away," he continued.

Meanwhile, Ukraine has intensified its strikes deep into Russia using Western-provided weapons, with the NATO chief calling Kiev's allies to allow Kiev to use supplied weapons without restrictions in a recent address.

Earlier this month, US Secretary of State Antony Blinken reportedly urged the administration after an unexpected trip to Kiev to let Ukraine use American weapons as it sees fit.

However, Western countries remain cautious not to trigger a direct clash between the coalition and Russia, especially with some members of the coalition stating intentions to deploy troops in Ukraine.

'NATOization of Europe'

Russia has been warning for decades against NATO's expansion toward its borders. Prior to the war in Ukraine, and following Ukrainian President Volodymyr Zelensky's remarks about deploying nuclear weapons in his country, President Vladimir Putin said that to maintain calm and security in the region, Ukraine must commit to "neutrality" and not a center of threat at Russia's border.

The US president claimed that during a conversation with Putin in 2021, he told Russia's leader that demanding a neutral Ukraine would result in the "NATOization" of the entire Europe.

"Putin was certain that NATO would fracture," Biden stated. "Today the greatest defense alliance in the history of the world is stronger than ever."

Read more: NATO states to build 'drone wall' across northwestern Russian borders

In response to escalating Western hostility, Russia launched last week the first stage of military drills for the preparation and use of non-strategic nuclear weapons, in its southern military district.

A statement issued by the Russian Defense Ministry said "practical testing of the preparation and use of non-strategic nuclear weapons" was ordered by the Supreme Commander-in-Chief of the armed forces of the Russian Federation, under the supervision of the General Staff.

The ministry affirmed that the drills aimed at maintaining Russia's readiness to secure its sovereignty.