A bill creating the legal framework for the annexation of Crimea will be considered by the State Duma on March 21, Vyacheslav Nikonov, a lawmaker from the United Russia party, said Tuesday.
The current law stipulates that a foreign territory can only join Russia by signing a treaty with the state that it belongs to.
The bill would amend this process to account for territories that are not controlled by a sovereign state that is effectively protecting the rights of its citizens. In this situation, a foreign territory can join Russia on the basis of a referendum.
Deputies from the A Just Russia party drafted the bill in response to the events in Ukraine, where President Viktor Yanukovych was ousted in a move that the Kremlin has described as a coup by fascist militants.
Authorities in Crimea are holding a referendum on Sunday to decided whether to expand the southern Ukrainian region's autonomy, paving the way for the peninsula to become part of Russia.
The West and the interim government in Kiev have said that the referendum is illegal and have vowed not to recognize the outcome.