MOSCOW (BLOOMBERG) - Russia has appointed a new commander for its operations in Ukraine as it refocuses its war effort in the east, having failed to secure territory around the capital, Kyiv.

General Alexander Dvornikov, commander of the Southern Military District, will now lead Russian troops on the ground, according to Western security officials and diplomats with knowledge of the change. The Kremlin has not announced the appointment.

General Dvornikov, 60, has held several senior positions in the Russian military, including army commander of the Far Eastern Military District.

He notably oversaw Moscow's forces in Syria in 2015 and 2016, where they fought alongside Syrian government troops in a conflict where President Bashar al-Assad was accused of using chemical weapons against his own people.

With the war in its seventh week, Russia has largely withdrawn its forces from the north after its troops faced fierce resistance and became bogged down outside Kyiv. Moscow also lost numerous tanks and aircraft due to missile attacks by Ukraine.

Now, Moscow is focused on the eastern Donbass regions and taking towns and cities in the Black Sea area, including Mariupol, which has been under siege for weeks already. Doing so would allow it to create a land bridge between Crimea, which it annexed in 2014, and Russia.

Still, "no appointment of any general can erase the fact that Russia has already faced a strategic failure in Ukraine", US National Security Advisor Jake Sullivan said on Sunday (April 10) on CNN's "State of the Union."

"It doesn't matter which general President Putin tries to appoint," he said. "But, as you noted, this particular general has a resume that includes brutality against civilians in other theaters, in Syria. And we can expect more of the same in this theater."

Ukraine, the US and other nations have accused Russian troops of committing war crimes in towns they occupied in the north, including Bucha, where mass graves were discovered of civilians as Russian forces withdrew.