MOSCOW, Russia - Russian President Vladimir Putin announced Thursday a military operation in Ukraine to defend separatists in the east of the country.

"I have made the decision of a military operation," he said in a surprise statement on television shortly before 6 am (0300 GMT).

• 'Major war in Europe' could be started by Russia soon: Ukraine leader

Ukrainian President Volodymyr Zelensky said Thursday that Russia could start "a major war in Europe" in the coming days and urged Russians to oppose the attack.

• UK warns Russia could start Europe's 'biggest war since 1945'

In an address aired shortly after midnight Zelensky said Russia could invade Ukraine "any day now" and, addressing the Russian people, said whether that happens "depends on you."

"Who can stop (the war)? People. These people are among you, I am sure," he said.

Zelensky said he had tried to call Russian President Vladimir Putin but there was "no answer, only silence", adding that Moscow now had around 200,000 soldiers near Ukraine's borders.

Rebel leaders in eastern Ukraine have asked Moscow for military help against Kyiv, the Kremlin announced late Wednesday, in a move that opens the door for massed Russian troops to move in.

Separatist leaders of Donetsk and Lugansk sent separate letters to Putin, asking him to "help them repel Ukraine's aggression," Putin's spokesman Dmitry Peskov said.

The two letters were published by Russian state media and were both dated February 22.

Their appeals came after Putin recognized their independence and signed friendship treaties with them that include defense deals.
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