Signs are growing that Ukrainian forces have penetrated the first line of Russian defenses along part of the southern front lines in Zaporizhzhia region, and are expanding a wedge in the direction of the strategic town of Tokmak.

The Ukrainian General Staff said Friday there had been further success in two areas -- towards the village of Novoprokopivka and further east in the direction of another small settlement, Ocheretuvate.

Earlier this week, the Ukrainians said they had secured the village of Robotyne. Fighting continues to the south of that village.

The General Staff said units "are consolidating their positions, inflicting artillery fire on the identified enemy targets, and conducting counter-battery operations."

Several Russian military bloggers have painted a gloomy picture of the front line situation in parts of the south.

One of the best-known of these, "WarGonzo," said the Ukrainians had gained a foothold in Robotyne "and are attacking Novoprokopivka, which is under heavy shelling."

Ukrainian forces have also launched a parallel attack in the Verbove area to the east -- amid heavy artillery fire in both directions.

A blogger called "Rogozin at the front," who is linked to the Russian 58th Combined Arms Army, said there had been an accumulation of enemy armored vehicles.

"The enemy is gathering forces for a decisive blow. They need to reach Verbove, then Tokmak," he wrote. "We're holding out."

Another blogger, "Belorusky silovik" [Belarusian Enforcer], said "the biggest worry right now is Robotyne. The boys are having it really hard there. By the evening the fighting was already going on in the south of the settlement, where the enemy was."

"It is objectively beginning to feel that there is a lack of new blood at the front," the blogger wrote.

"Otryady Kadyrovtsy" [Kadyrov Detachments] painted a similar picture, saying: "Heavy fighting continues in the Robotyne area. The bastards are rapidly advancing, covered by artillery strikes."

The blog said Ukraine was using aviation to cover advancing infantry and had brought more ammunition supplies into the area of Mala Tokmachka.

Another Russian blogger said this was a critical moment on the battlefield, adding that Russian forces need to hold their positions for at least another month and a half to try to make gains in another area of the frontline and attempt to shift the battlefield situation.

On Thursday, the spokeswoman for Ukraine's southern command, Nataliya Humenyuk, said Russian forces were bringing more forces to the Zaporizhzhia area from Kherson to the south, due to the heavy casualties among units already there.

Yurii Malashko, head of Zaporizhzhia region military administration, said there were almost no buildings left standing in Robotyne after weeks of fighting in the area.

"Our soldiers are slowly moving forward, but the mine barriers they [the Russians] have set up are very large, and it takes time to get through them."

In its latest assessment, the Washington DC-based Institute for the Study of War (ISW) said Ukrainian forces "advanced closer to the Russian second line of defense in the Robotyne area ... further widening their breach of Russian defensive lines in the area."

ISW said "Russia's lack of operational reserves will force the Russian command to conduct additional redeployments as Ukrainian counteroffensive operations continue to degrade defending Russian forces in several sectors of the front."

Kyiv pushing to break Russian land-bridge

Ukrainian attacks in the area are part of Kyiv's effort to push down to the Sea of Azov.

The area is a major target for Ukraine as pushing deep into the territory would mean breaking Russia's land-bridge between annexed Crimea and eastern Donetsk.

The ISW previously said even marginal gains by Ukraine in this area are significant.

"The Ukrainian forces' ability to advance to the outskirts of Robotyne -- which Russian forces have dedicated significant effort, time, and resources to defend -- remains significant even if Ukrainian gains are limited at this time," the ISW said.

Ukraine's highly anticipated counteroffensive has been underway for weeks with fighting focused along the eastern and southern fronts.

Kyiv launched the campaign in the hope of recapturing territory seized by Russia. But so far, any gains have been small and painfully fought for.