Factbox-The four regions that Russia is poised to annex from Ukraine

A bird flies above a banner on a screen, set up ahead of an expected ceremony and concert to declare four Ukraine's self-proclaimed regions part of Russia following recent referendums, near St. Basil's Cathedral in central Moscow, Russia September 29, 2022. A slogan on the screen reads: "Donetsk, Luhansk, Zaporizhzhia, Kherson - Russia!" REUTERS/Evgenia Novozhenina

Russian President Vladimir Putin will proclaim the annexation of four Ukrainian regions at a Kremlin ceremony on Friday, a major escalation in the seven-month war. Ukraine and the West have denounced the moves - as they did with Moscow's 2014 seizure of Crimea - as illegal seizures after what they called sham referendums held at gunpoint.

Here are some details of the four regions - each roughly the area of the U.S. state of Massachusetts and together comprising about 15% of Ukraine's land area - and the varying extents to which Russia has already brought them under its control by military, economic and other means.