Editor's note: This is a breaking news story and is being updated.
Ukraine's 3rd Separate Assault Brigade launched a counterattack in Kharkiv Oblast and advanced almost 2 square kilometers deep into the front line area, the brigade said on Aug. 22.
Earlier in the day, the brigade released a video showing what it claims was the first footage of an "offensive in full swing" filmed in the eastern region.
"The main aim of the operation was to bring down the offensive potential of the 20th Army of the Russian Federation. At the moment, this task has been accomplished," Brigade Commander Andrii Biletskyi said.
It is unclear when the attack was launched, its scale, and the area of the offensive. The brigade said that Russia lost around 300 soldiers in four days, and "a significant amount of equipment and weapons were broken or damaged."
Ukrainian soldiers also took control of a battalion defense area of Russian troops and some Russian strongholds, according to the statement.
The Kyiv Independent could not verify these claims.
"The assault operations prevented the enemy's attack from the direction of Makiivka and relieved tension from other critical frontline areas in the neighboring brigades' zones," the brigade said.
The village of Makiivka in Luhansk Oblast is located some 180 kilometers (111 miles) southeast of the city of Kharkiv.
According to Biletsky, Ukrainian forces attacked Russian troops that had superiority "and won." The ratio of forces on the battlefield was 2.5:1 in Moscow's favor, the statement read.
"The success depended on detailed planning, non-standard solutions, coordinated work of artillery, air defenses, and intelligence," the commander said.
After Ukraine's reported counterattack, Russia's forces are stepping up the use of aircraft and other weapons, attempting to regain lost ground, the brigade said.
The 3rd Separate Assault Brigade is known to have been operating around the village of Borova in Kharkiv Oblast, as it reported the thwarting of a Russian attempt to make a breakthrough in the area in early July.
While initially gaining ground in May, a Russian offensive in northeastern Kharkiv Oblast quickly bogged down, with Russian troops reportedly suffering heavy losses.
The intensity of fighting had decreased somewhat compared to other sectors, though several reports of Russia preparing new attacks have emerged since then.