In more detail, Russian forces have been trying to take Bakhmut for months, and Koshel has been delivering supplies to the frontline there.
He recounts the stories of Ukrainian soldiers embedded there, who claim that Russian forces killed their comrades with axes.
They also reportedly took pictures of the dismembered bodies and shared them.
Though the story is graphic and distressing, Koshel believes the soldiers' accounts are true.
The Ukrainian military has not yet confirmed this.
However, Ukrainian President Volodymyr Zelensky has said that Russian violations of the ceasefire in the eastern Donbass region have risen in recent months.
He claims that Russian-backed separatists have killed 14 Ukrainian soldiers this year alone.
Meanwhile, the US and its Western allies have been sending military aid to Ukraine, in order to help them defend themselves against Russia.
Russian officials have not yet commented on the allegations made against their forces in Bakhmut.