Russia has lost approximately five soldiers for every Ukrainian soldier killed in the battle for the eastern city of Bakhmut, CNN reported late Monday, citing NATO estimates.Moscows forces, led by fighters from the Wagner mercenary group, have been waging brutal fighting for Bakhmut since August, taking severe casualties in pursuit of what would be Russias first battlefield win in months.An unidentified NATO official told CNN that the five-to-one death ratio was an informed estimate based on the United States -led military blocs intelligence.Despite the favorable ratio for Ukraines forces, the NATO official noted that Ukraine was suffering significant losses in its defense of the city.Ukraine has vowed to keep up its defense of Bakhmut, a former salt-mining city that now lies in near-total ruin.Kyiv this week said the fighting had become increasingly difficult and analysts said its forces may have initiated a strategic retreat.But President Volodymyr Zelensky met with top commanders Monday and his office said they favored "continuing the defensive operation and further strengthening our positions in Bakhmut."In his evening address, the president said he "told the Chief of Staff to find the appropriate forces to help the guys in Bakhmut."The United States -based Institute for the Study of War said that Russias push to capture Bakhmut has significantly deteriorated its capacity to carry out additional offensives in its year-long war on its neighbor.The Russian military will likely struggle to maintain any subsequent offensive operations for some months, giving Ukraine a chance to seize the initiative, the think tank said Monday.AFP contributed reporting.