President Vladimir Putin will hold a signing ceremony in the Kremlin on Friday to add four territories of Ukraine into Russia, his spokesman said.
Kremlin spokesman Dmitry Peskov said a signing ceremony would take place at 1200 GMT on Friday "on agreements on the accession of new territories into the Russian Federation."
Agreements will be signed "with all four territories that held referendums and made corresponding requests to the Russian side," Peskov said.
The votes were cast in the West as illegal and illegitimate. Putin's decision to incorporate the regions into Russia means Moscow will annex vast areas across eastern and southern Ukraine, representing around 15% of Ukraine's total territory.
Russian-backed officials in four regions of Ukraine controlled by Russian forces said referendums showed overwhelming majorities of their populations had voted to join Russia in votes slammed by Ukraine and the West as "shams."
Following the signing ceremonies in the Kremlin, Putin will give a major speech and will meet with Moscow-appointed administrators of the Ukrainian regions, the Kremlin said.
