Watch: Putin threatens to use nuclear weapons. "It's not a bluff."

In a televised address today, Russian Prime Minister Vladimir Putin announced a mobilization of troops—its first since World War II—and threatened the use of nuclear weapons in defense of Russian. "I'm not bluffing," he said. Video above. From The Guardian:

The Russian leader's televised address to the nation comes a day after Russian-controlled regions in eastern and southern Ukraine announced plans to hold "referendums" this weekend on becoming part of Russia. Kremlin's plans to annex four regions are likely to further escalate the war following Ukrainian recent successes on the battlefield.

"To those who allow themselves such statements regarding Russia, I want to remind you that our country also has various means of destruction, and for separate components and more modern than those of Nato countries and when the territorial integrity of our country is threatened, to protect Russia and our people, we will certainly use all the means at our disposal," Putin said.

He added: "It's not a bluff."