President Vladimir Putin signed a decree Friday on the ratification of the treaty providing for the reunification of the Crimean Peninsula with Russia.
The treaty had been already ratified by both houses of parliament.
Under the decree, Russia will have 85 regions, up from the previous 83. The Republic of Crimea and the city of Sevastopol, which has a special status within the region, were added as subjects of the Russian Federation following a referendum Sunday in the Black Sea region, which saw over 96 percent of voters in the region back the motion to rejoin Russia.
Putin along with Crimean Prime Minister Sergei Aksyonov and other leaders of the region signed an agreement Tuesday in the Kremlin stating the Crimea was to be considered part of Russia with immediate effect.