Russia's deputy defence minister Dmitry Bulgakov has been removed from office and transferred to "another post," the Defence Ministry in Moscow said on Saturday.
He is to be replaced by Colonel General Mikhail Mizintsev, who was seen as responsible for the heavy attacks on the southern Ukrainian city of Mariupol which was captured by Russia at the end of May.
Thousands of civilians were killed during the siege, Ukraine says.
Mizintsev had been head of the national centre for defence management. From now on, he will be responsible for the armed forces' logistics.
The Russian military leadership under Defence Minister Sergei Shoigu has recently been criticized in circles close to the Kremlin. Some two weeks ago, Moscow's army had withdraw from the eastern Ukrainian region of Kharkiv, under pressure from Ukrainian counter-offensives.
