“Specifically on the axes of advance that (Ukrainian forces) are attacking right now, (Ukrainian forces) have attacked through the main defense belt,” Milley told Al-Mamlaka Television.

Ukrainian troops earlier in the week captured the strategic village of Robotyne in the Zaporizhzhya Oblast in Southeast Ukraine.

Russian military outlets were citing heavy losses on the Ukrainian side, according to CNN, which reported that signs of progress in the counteroffensive are evident in the Zaporizhzhia region as Ukrainian forces seek to expand a wedge toward the strategic town of Tokmak.

Attacks on Russian-occupied Crimea are also being stepped up. Ukrainian Intelligence Directorate official Andriy Yusov said Friday an attack was made on Russia’s Black Sea Fleet at the village of Perevalne, destroying the fleet’s 126th Separate Guards Coastal Defense Brigade.

Milley admitted during the interview that the Ukrainian counteroffensive has moved at a slower than expected pace — Ukraine first launched the long-awaited military counteroffensive in June.

The U.S. general said it remains far too early to be able to call the counteroffensive a success or failure, characterizing the effort as “very bloody, slow, long and difficult.”

“It is still too early to judge the success or failure of the attack…It is clear that so far partial success has been achieved,” he said.

Many other top military leaders continue to reserve judgment on the counteroffensive, although Giampaolo Di Paola, Italy’s former defense minister and chairman of NATO’s military committee, said Ukraine has seized the initiative from invading Russian forces.

“The pace is slow. The Ukrainians keep saying it’s going as planned. I don’t know whether it’s true or not,” he said in an interview Friday with Radio Free Europe. “What has been achieved is that Ukraine has retaken the initiative from the enemy. We saw the long-awaited counteroffensive finally happening.”