POSTED: Tuesday, March 18, 2014 - 4:51am
UPDATED: Wednesday, March 19, 2014 - 11:22am
MOSCOW (CNN) — Russian President Vladimir Putin has formally notified his nation's parliament of Crimea's accession request, the Kremlin announced Tuesday.
The move comes a day after Putin signed a decree recognizing Ukraine's Crimea region as a sovereign state.
In Sunday's contested referendum in Crimea, 97% of voters cast ballots in favor of divorcing Ukraine and becoming part of Russia. U.S. President Barack Obama dismissed the vote as illegal.
"The international community will continue to stand together to oppose any violations of Ukrainian sovereignty and territorial integrity, and continued Russia military intervention in Ukraine will only deepen Russia's diplomatic isolation and exact a greater toll on the Russia economy," Obama said.
Western powers slapped sanctions on more than two dozen Russian officials and their allies in Crimea, while Ukrainian officials vowed they would never accept the territory's annexation by Russia.
Putin is due to address a joint session of the Russian parliament Tuesday.
A number of procedural steps must be followed in order to add new members to the Russian Federation
But the speaker of Russia's upper house of parliament, Valentina Matvineko, told state-run Russia-24 TV that the process need not take long, the official news agency Itar-Tass reported.
"We shall be acting strictly in compliance with the law. The procedure will not take long. All can be done rather promptly," she is quoted as saying.
Yatsenyuk: We offer peace
Russia's military activities in Crimea and its backing for the region's secession bid has been condemned by Ukraine's interim government in Kiev, the European Union and the United States.
French Foreign Minister Laurent Fabius and a French delegation have postponed a planned visit to Moscow because of the Ukrainian situation, the Russian Foreign Ministry said Tuesday.
In a televised address Monday night, interim Ukrainian President Oleksandr Turchynov said his government would do "everything possible" to solve the crisis diplomatically, and he praised his citizens for refusing to respond to Russian provocations with violence.
"The Kremlin is afraid of the democratic future which we are building, and this is the reason for their aggression," Turchynov said. "But this will not be an obstacle to the building of a democratic country."
But he announced a partial mobilization of his country's armed forces and said Ukrainians "have to unite in one big family, which is ready to protect its home."
Prime Minister Arseniy Yatsenyuk said there was "a strong possibility" of a Russian invasion of Ukraine.
"I still believe that there is only one solution of this crisis, a peaceful one," Yatsenyuk said. "But we offer peace, and Russia offers war."
The EU sanctions include the top pro-Russian Crimean secessionist leaders, 10 leading Russian lawmakers who have endorsed the annexation of Crimea and three top Russian military commanders.
The U.S. sanctions list also includes two top advisers to Russian President Vladimir Putin and ex-Ukrainian President Viktor Yanukovych, whose February ouster in the face of widespread anti-government protests prompted the current crisis.
The protests were first sparked in November by Yanukovych's decision to turn away from a planned trade deal with the European Union in favor of closer ties with Russia.
CNN's Alla Eshchenko reported from Moscow and Laura Smith-Spark wrote in London. CNN's Matt Smith and Marie-Louise Gumuchian contributed to this report.