President Joe Biden said Friday that the United States will "never" accept Russia's annexation of part of Ukraine seven years ago.

"The United States does not and will never recognize Russia's purported annexation of the peninsula, and we will stand with Ukraine against Russia's aggressive acts," Biden said in a statement marking the anniversary of the Russian invasion of Crimea.

"The United States continues to stand with Ukraine and its allies and partners today, as it has from the beginning of this conflict. On this somber anniversary, we reaffirm a simple truth: Crimea is Ukraine," Biden said.

Russian troops seized the Crimean peninsula on the Black Sea coast of Ukraine in 2014 and President Vladimir Putin then incorporated the region under Moscow's rule.

Simultaneously, the Kremlin backed an armed uprising in eastern Ukraine where pro-Russian separatists declared independence, sparking a war that continues to simmer, with swaths of territory remaining out of the Ukrainian government's control.

In this file photo taken on December 07, 2015, then-US Vice President Joe Biden speaks in Kiev, Ukraine
In this file photo taken on December 07, 2015, then-US Vice President Joe Biden speaks in Kiev, Ukraine POOL / Sergey SUPINSKI

In the latest fighting, two people were killed and two injured, the government in Kiev said Wednesday.

The latest casualties came as Kiev accused Moscow and the separatists of using heavy weaponry and ramping up attacks in violation of a ceasefire agreed in July of last year.

sms/dw