Experts claim that Russia has made "negligible gains" in its military campaign.
ADVERTISEMENTRussia has lost territory "larger than Denmark" during its war with Ukraine, according to a leading think tank.
Experts say Russian forces have been pushed back across 45,000 km2 of land since 21 March, when they had made their deepest advance into Ukraine.
The report by the Institute for the Study of War (ISW) claims that Russia has made "negligible gains" in its military campaign.
On Wednesday, Russian Defence Minister Sergei Shoigu said its operation in Ukraine had been deliberately slowed down to avoid civilian casualties.
But researchers at the Washington-based ISW say this may be an attempt to "explain and excuse" the military's "negligible gains".
"Shoigu's statement may also represent an attempt by the Russian MoD to set information conditions to explain and excuse the negligible gains Russian forces have made in Ukraine in the last six weeks," the ISW said.
Since Russia stepped up an offensive in mid-July, it had gained just over 450 square kilometres of new territory in Ukraine, equivalent to "an area around the size of Andorra", it said.
However, the ISW added that territorial losses since March were 100 times greater.
"Russian forces have lost roughly 45,000 km2 of territory since March 21 (the estimated date of Russian forces’ deepest advance into Ukraine), an area larger than Denmark," it reports.
"Russian forces are unable to translate limited tactical gains into wider operational successes, and their offensive operations in eastern Ukraine are culminating. Shoigu’s statement is likely an attempt to explain away these failings."