Since the violence between pro-Russian rebels and Ukrainian forces began last April, the UN estimates some 2,600 people have been killed and thousands more have been wounded.
What one side sees as a fight against terrorism, the other sees as a fight for their rights.
One Ukrainian soldier who survived an ambush said his comrades were demoralised, ill-equipped and unprepared.
The government-backed Donetsk regional governor Serhiy Taruta sees no-one emerging as an eventual winner:
“If there is a full-scale military invasion, this will be war. A war between Ukraine and Russia. And it’s not a given that Russia will certainly win. Because there will be guerrilla movements, there will be a huge number of those who would want to defend their motherland with weapons in their hands. I think this path is hopeless for Russia. And Ukraine doesn’t need it either.”
Some wounded Ukrainian troops are now being flown out to Germany for treatment as the number of casualties climbs.
Along with the dead and injured, the ongoing fighting around Donetsk Luhansk and neighbouring towns is said to have forced more than a million people from their homes.