It follows Sunday's referendum in which officials say nearly 97% of Crimeans voted to break away from Ukraine.
The government in Kiev has said it will not recognise the results. The US and EU say the vote was illegal and have vowed to impose sanctions on Moscow.
The Crimean peninsula has been under the control of pro-Russia forces since late February.
Moscow says the troops are pro-Russian self-defence forces and not under its direct control.
The crisis follows the ousting of Ukraine's pro-Moscow president Viktor Yanukovych on 22 February, following months of street protests and deadly clashes.
According to the vote in Crimea's parliament on Monday, Ukrainian laws no longer apply in the region and all state Ukrainian state property belongs to Crimea.
Meanwhile, the Ukrainian parliament in Kiev formally approved the partial mobilisation of 40,000 reservists, in response to what it called the "war-time situation".
Speaking in parliament, interim President Oleksandr Turchynov described the referendum as a "great farce" which "will never be recognised either by Ukraine or by the civilised world".