The report is the first official confirmation of the scale of a defeat in the city of Ilovaisk that critics of the country's military command have described as the result of disastrous leadership.
It is believed the ultimate number of servicemen lost may be even greater, and the parliamentary inquiry into the Ilovaisk battle complained that military authorities have failed to cooperate.
"Neither the Defense Ministry nor the General Staff has responded to queries from the investigating committee about losses in the armed forces," the committee said in a statement.
The city and surrounding villages still bears signs of heavy shelling.
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A cease-fire deal struck a month ago by Ukraine's President Petro Poroshenko, Russian President Vladimir Putin and the rebel leadership is often violated.
German Chancellor Angela Merkel said today "there's a long way to a cease-fire, unfortunately," given the number of people who have been killed since the deal was struck.
Europe is seeking full compliance with the cease-fire, clear border controls and local elections in eastern Ukraine in compliance with Ukrainian law, and not under auspices of the rebels.
The UN estimates more than 300 people have been killed since the cease-fire was announced, and at least 3,660 people have been killed over six months of fighting.
In Ilovaisk city in August, government troops sustained heavy losses of life attempting to flee the area and were easily picked off by rocket and artillery fire as they fled in columns.
AP reporters counted more than 30 charred Ukrainian military vehicles on the route out of the city in early September, when the battle had come to a close.