The Institute for the Study of War, a US-based think tank, said Russian forces gained 175.54 sq km in some sectors of the front last month while losing 256.35 sq km in others, producing a net loss of 80.81 sq km. Counting Russian incursions into territory they did not establish control over, the net loss rises to 175.18 sq km, the institute said.

Speaking on October 1 at the plenary session of the Valdai Discussion Club, an annual forum attended by Russian and foreign analysts and officials, Putin said Russia had placed 1,301 sq km under its control in September and called it "2.5 times more than in previous months." He also said Moscow considered the full capture of the Donetsk region a matter for a nearer term than Europe and Ukraine believe, and added that there was no point for Kyiv to "cling" to territories whose loss is inevitable.

ISW called Putin's statements so far removed from reality that they "resemble hallucinations." The institute said such remarks create a fictional picture of the battlefield and align with the Kremlin's efforts to present the situation in a favorable light, The Moscow Times reported, citing the ISW report.

ISW stopped short of asserting whether Putin knows the figures he cited are inaccurate. The institute suggested the president may be receiving distorted data from his military command, a practice it linked to a culture of concealing failures within the Russian military structure.

According to the institute, the last time Russia lost territory in Ukraine over a full month was May, when the figure was 281.1 sq km. Losses in April were estimated at 116.01 sq km. Over the summer, ISW recorded modest growth in captured area: 30 sq km in June, 38 sq km in July and 90 sq km in August.

The accounts diverge: Putin said on October 1 that Russia had seized 1,301 sq km of Ukrainian territory in September, while ISW recorded net Russian territorial losses of 80.81 sq km for the same month, or 175.18 sq km counting incursions without established control.