Russian Defense Minister Sergei Shoigu on Tuesday described Ukraine's counteroffensive as completely unsuccessful, but said the situation in part of the southern Zaporizhzhia region which Russia controls was tense.

"Ukraine's armed forces have not achieved their goals on any front," the defense ministry quoted Shoigu as saying.

"The most tense situation is that on the Zaporizhzhia front," he said.

"The enemy has engaged brigades from its strategic reserve whose personnel have been trained by Western instructors."

By taking control of parts of Ukraine, Russia has established a "land bridge" to Crimea, the Black Sea peninsula which it annexed in 2014.