MOSCOW (AP) -- Russia's President Vladimir Putin on Tuesday approved a draft bill for the annexation of Crimea, a key move in a flurry of steps to formally take over the Black Sea peninsula.
Russia's Constitutional Court and the Kremlin-controlled parliament are expected to quickly endorse the move. Some lawmakers said that Crimea could be made part of Russia by the end of the week.
Crimea on Sunday voted overwhelmingly to secede from Ukraine and seek to join Russia. The hastily called vote was held two weeks after Russian troops had overtaken the Black Sea peninsula.
The West and Ukraine described the referendum, which was announced two weeks ago, as illegitimate.
The United States and the European Union on Monday announced asset freezes and other sanctions against Russian and Ukrainian officials involved in the Crimean crisis. President Barack Obama warned that more would come if Russia didn't stop interfering in Ukraine.
France's Foreign Minister Laurent Fabius said on Europe-1 radio Tuesday that leaders of the Group of Eight world powers "decided to suspend Russia's participation, and it is envisaged that all the other countries, the seven leading countries, will unite without Russia."
The other seven members of the group had already suspended preparations for a G-8 summit that Russia is scheduled to host in June in Sochi.
Former Soviet President Mikhail Gorbachev, however, hailed Crimea's vote to join Russia as a "happy event." Gorbachev, in remarks carried Tuesday by online newspaper Slon.ru, said Crimea's vote offered residents the freedom of choice and showed that "people really wanted to return to Russia."
Gorbachev added that the referendum set an example for people in Russian-speaking eastern Ukraine, who also should decide their fate.
The decree signed by Putin and posted on the official government website Tuesday morning is one of the steps to formalize the annexation of Crimea. Putin was set to address both houses of the parliament at 3 p.m. Moscow time (1100 GMT) in a nationally televised speech where he was widely expected to stake Russia's claim on Crimea and spell out his further policy in the Ukrainian crisis.
Putin has warned that he would be ready to use "all means" to protect Russian speakers in eastern Ukraine, and Russia has built up its forces alongside the border between the two countries, raising fears of an invasion.
Ukraine's Prime Minister Arseniy Yatsenyuk said in a televised statement that Ukrainian law-enforcement agencies have gathered "convincing evidence of the participation of Russian special services in organizing unrest in the east of our country."
Many in the ethnic Tatar minority in Crimea were wary of the referendum, fearing that Crimea's break-off from Ukraine would set off violence against them.
Crimean Deputy Prime Minister Rustam Temirgaliyev seemed to confirm those fears, saying in remarks carried by the RIA Novosti news agency that the government would ask Tatars to "vacate" some of the lands they "illegally" occupy so authorities can use them for "social needs."
The Russian State Duma, the lower chamber of parliament, on Tuesday unanimously passed a resolution condemning U.S. sanctions targeting Russian officials including members of the chamber. The chamber challenged President Barack Obama to extend the sanctions to all the 353 deputies who voted for Tuesday's resolution, suggesting that being targeted was a badge of honor. Eighty-eight deputies left the house before the vote.
Crimea had been part of Russia since the 18th century until Soviet leader Nikita Khrushchev transferred it to Ukraine in 1954. Both Russians and Crimea's majority ethnic Russian population see annexation as correcting a historic insult.
Ukraine's turmoil, which began in November with a wave of protests against President Viktor Yanukovych and accelerated after he fled to Russia in late February, has become Europe's most severe security crisis in years.
Jim Heintz in Kiev, Angela Charlton in Paris and Vladimir Isachenkov in Moscow contributed to this report.