Ukraine launched its long-awaited counteroffensive against Russia on June 8, ABC News reported, citing unnamed Ukrainian official sources, one of them supposedly close to President Volodymyr Zelensky.
The hostilities are reportedly taking place in southeastern Ukraine, south of the city of Zaporizhzhia.
Ukraine's troops include specialized attack units armed with Western weaponry and trained in NATO tactics, the Washington Post wrote.
Russian military bloggers also claim heavy fighting in Zaporizhzhia Oblast.
Kyiv's advance south in this direction may sever the land corridor between mainland Russia and occupied Crimea, thus cutting off Russian supply lines.
On June 3, Zelensky announced that the Armed Forces of Ukraine were ready for the long-awaited counteroffensive against Russian forces.
Russia claimed that the counteroffensive began already on June 5, adding that its forces had successfully repelled it without providing evidence.
Ukraine's Defense Ministry refuted Russia's claim, calling it a diversion effort. At the same time, the military reported advances in the Bakhmut direction and "other areas" on June 6.