Ukrainian officials indicated Thursday that further inroads have been made on the southern front, with some units advancing "deep into the Russian defenses" -- a possible sign of progress amid Kyiv's grinding counteroffensive.

Colonel Mykola Urshalovych, Deputy Director of Planning with the National Guard, said at a briefing in Kyiv that "in the Melitopol sector, units of the Offensive Guard brigades are pushing the occupiers out of their positions and consolidating their positions despite strong Russian resistance."

Urshalovych also claimed that "Despite dense mining and engineering equipment, as well as strong resistance from the occupiers, our units had a partial success, advanced both into the depths of the enemy's defense and along the front."

Russian-appointed officials in occupied Zaporizhzhia give a very different picture. Vladimir Rogov, a member of the Russian-installed Zaporizhzhia military-civilian administration, said there had been a strike on a Ukrainian assault group in the Robotyne area, where heavy fighting has continued for some two months.

Russian news agency RIA Novosti quoted Rogov as saying: "Our attack drones have hit an assault group of Ukrainian militants who tried to break through to our positions on the Orikhiv direction between the villages of Robotyne and Verbove."

Rogov said the Ukrainians were forced to retreat with heavy losses.

However, another Russian-appointed official implied that Ukrainian reinforcements in the area might lead to a deterioration of the defensive situation.

Yevgeniy Balitskiy, the acting governor of occupied parts of Zaporizhzhia region, said on Telegram that "the enemy is completing the redeployment of its units in the Robotyne area, after which we expect the situation in the Robotyne-Verbove area to deteriorate."

But he continued: "We understand that the enemy has no success to count on, the morale of the Armed Forces of Ukraine is very low, but the time for the 'quarterly report' to [their] Western curators is approaching for the Kyiv leaders -- and they vitally need a 'victory.'"

CNN is unable to verify the battlefield reports of either side. However, open-source analysis of available video suggests that some Ukrainian units have crossed through an important line of Russian defenses near the village of Verbove.

According to several analysts, Ukrainian vehicles from the 82nd Air Assault Brigade had crossed one trench system. The open-source investigative group GeoConfirmed wrote that the "Russian defensive line consisted of an anti-tank ditch, dragons teeth and a trench system."

It said that reconnaissance elements had achieved a foothold in the trench system, "followed by infantry units to clear the trenches...The treelines are full of trenches and defensive positions that need to be cleared before vehicles can come closer."

GeoConfirmed posted video showing armored vehicles crossing the trench system, with the comment "Marder and Stryker assault west of Verbove behind the main line." It's unclear when the drone video was shot.

A Ukrainian officer with extensive experience in reporting on front line changes said on X: "It's evident that our forces executed maneuvers effectively, driving back the enemy and exploiting the gap. They have advanced close to Verbove, overcoming [anti-tank] trenches, minefields, and dragon's teeth. A notable milestone...The next several days will show if the penetration becomes a breakthrough."

Kyiv's troops have been attempting to push forward for months as part of a counteroffensive aiming to recapture Russian-seized territory. So far, however, gains have been marginal and won at a great cost.

Without air superiority and in the face of dense minefields and reinforced Russian units, Ukrainian forces have so far struggled to break through the multiple layers of Russian defenses in occupied Zaporizhzhia on the southern front.

They still remain some 20 kilometers from the strategic Russian hub of Tokmak, their first major target on the southern offensive.

Ukrainian President Volodymyr Zelensky has said that securing air defenses is among the top issues on his agenda as he visits Washington DC on Thursday.

Thursday's development comes after Ukrainian Deputy Defense Minister Hanna Maliar on Monday told CNN her country has been able to liberate 300 square kilometers since the beginning of Ukraine's counteroffensive in the summer.

"In total during the summer campaign we liberated 300 square kilometers," Maliar told CNN, downplaying the number and highlighting the tough conditions Ukrainian forces have been able to overcome.