Russia's Constitutional Court on Sunday recognized as lawful the annexation treaties of Ukraine's four breakaway regions.
The court ruled that the treaties on the admission of the self-proclaimed Donetsk People's Republic and Luhansk People's Republic, as well as the Kherson and Zaporizhzhia regions, to the Russian Federation were constitutional.
Russian President Vladimir Putin on Friday announced the "accession" of the four regions to Russia.
Putin said the results of the referendums in those regions late last month were clear and that local residents had "made their choice."
On Sept. 23-27, the Ukrainian separatist regions of Donetsk and Luhansk and Russian-controlled parts of Zaporizhzhia and Kherson held referendums on joining Russia.
The referendums have been condemned by the international community, with European nations and the US calling them a "sham" and underlining that they would not be recognized.