Russia's military campaign against Ukraine is aimed at annihilating its eastern European neighbor's culture, US President Joe Biden said on Friday.

Biden said that not only is Russian President Vladimir Putin "trying to take on Ukraine, he is really trying to wipe out the culture and identity of the Ukrainian people."

Putin is "attacking school, nurseries, hospitals, museums with no other purpose than to eliminate a culture; a direct assault on the rules-based international order," Biden said during a graduation ceremony at the US Naval Academy in Annapolis, Maryland.

The comments come as Russia mounts its offensive on eastern Ukraine in the hopes of capturing the country's industrial heartland. The Kremlin previously withdrew from northern Ukraine amid stiff resistance from Kyiv's forces, and sought to recalibrate its assault on the eastern Donbass.

Ukraine said on Thursday that Russian troops are attempting to gain full control over Ukraine’s Luhansk and Donetsk regions, which collectively comprise the Donbass, but their efforts have been unsuccessful.

That comes as the Pentagon warns that Moscow's forces have been making "incremental gains" in the region. Spokesman John Kirby told reporters on Friday that "in the Donbass it gets a little bit more messy."

"Every day there's literally ground that's trading hands," he said in an indication of the territorial back-and-forth taking place as Ukraine mounts a "stiff resistance."

At least 4,301 civilians have been killed and 4,735 injured since the war in Ukraine began on Feb. 24, according to UN estimates. The true toll is believed to be significantly higher.

Over 6.6 million people have fled to other countries, while more than 7.7 million have been internally displaced, according to the UN refugee agency. That represents roughly one-third of Ukraine's pre-war population of 43 million people./aa