File Photo: Ukrainian People show their Russian passports sitting on a bus to Russia at a bus stop in Donetsk, eastern Ukraine, Saturday, June 27, 2020. AP
The decree ordered that "all citizens of Ukraine" be given "the right to apply for admission to the citizenship of the Russian Federation in a simplified manner".
In May, Putin already fast-tracked citizenship for residents of two regions of Ukraine, the southern region of Kherson, which is almost entirely under the full control of Russian troops, and the southeastern region of Zaporizhzhia, which is partially controlled by Moscow.
In 2019, a similar decree allowed the same simplified procedure for residents of the self-proclaimed Donetsk and Lugansk People's Republics, eastern Ukraine's breakaway regions.
Moscow and pro-Moscow officials in areas controlled by Kremlin troops have said they could become part of Russia.