After the referendum in Crimea, which resulted in an overwhelming majority of 97% voting in favour of seceding from Ukraine and joining Russia, Putin said in a televised statement that Crimeans were no longer prepared to put up with the "historical injustice" of being part of Ukraine.
"When Crimea suddenly became part of another state, Russia felt not only that something had been stolen from her, but that she had been mugged. Crimea has always been and remains an inseparable part of Russia," he said.
Always part of Russia
"In people's heart of hearts, Crimea has always been part of Russia," Putin told the Russian parliament. He said former Soviet Union leader Nikita Krushchev's decision to transfer Crimea to Ukraine in 1954 was unconstitutional.
In a reference to Ukraine's new leaders, who succeeded ousted president Viktor Yanukovich, Putin said:
"We can all clearly see the intentions of these ideological heirs of Bandera, Hitler's accomplice during World War II."
Stephan Bandera was a nationalist who saw in the Nazi Germany a powerful ally.
Putin defended Russia's invasion into Crimea as necessary to beat to a Western plot to take Ukraine.
He described the main figures in the Ukrainian uprising as "anti-Semites, Russophobes [who] determined a lot of what's happening in Ukraine".
"Russia could not step back any more. Russia has national interests that need to be respected."
Speaking of the collapse of the Soviet Union in 1991, Putin said: "The USSR broke up. The events happened so fast that few citizens understood the full scale of the trauma.
"[The USSR collapse] is the greatest geopolitical catastrophe of the 20th century, which left tens of millions of Russians outside the Russian Federation."