Russian President Vladimir Putin and Crimean leaders signed a treaty Tuesday to annex Crimea to Russia.
Gorbachev hailed the Crimean voters' decision to secede from Ukraine.
"While Crimea had previously been joined to Ukraine based on the Soviet laws, which means [Communist] party laws, without asking the people, now the people themselves have decided to correct that mistake," he said Monday.
"This should be celebrated, not sanctioned," he added.
About 60 percent of the population of Crimea is Russian speaking.
[The Moscow Times]