Kyiv and Moscow are believed to have suffered massive casualties after months of large-scale hostilities and the United States believes some 315,000 Russian soldiers have either been killed or wounded.

"The front line is over 2,000 kilometres (1,242 miles) long. There are 617,000 people in the conflict zone," Putin said during his first end-of-year press conference since sending his army into Ukraine in February 2022.

He added that some 244,000 mobilised troops were currently stationed in territories in Ukraine that are controlled by Russian forces.

Putin made the comments during his end-of-year press conference, where he said that there were no immediate plans to introduce a fresh round of mobilisation of Russian men for the conflict.