The Ukrainian armed forces said in a brief update late Friday that Russian forces are focused on ensuring the withdrawal of troops from the northern Kharkiv region. Those troops have come under growing pressure from Ukrainian counter-attacks along a wide front to the west of their supply lines.

The fierce counterattack has taken back a number of villages in the area east of Kharkiv. Ukraine's advances threaten the symbolic embarrassment of pushing the Kremlin's forces back to their own border, while posing the strategic threat of cutting Russia's supply lines into Ukraine and its forces further south in the Donbas region. It has also revealed further evidence of apparent Russian atrocities, according to a CNN team on the ground.

The General Staff on Friday also reported more cross-border shelling far from the current area of hostilities in the northeastern region of Sumy -- as well as an airstrike against a village in the region.

In the east of Ukraine, the General Staff said there had been more artillery shelling of Ukrainian-held territory as the Russians tried to make progress towards Sloviansk in the Donetsk region, a key objective. The village of Nova Dmytrivka had come under fire, it said, as it has done since late April. 

It also said that there had been airstrikes around Dolyna, which is 12 miles (20 kilometers) north of Sloviansk and nearby Adamivka. Airstrikes in the area earlier this week damaged two religious sites, according to Ukrainian authorities. 

In the Luhansk region, the General Staff said a Russian attack on the town of Zolote had been repulsed.