DHAKA: Ukraine is drawing up plans to withdraw its soldiers and their families from Crimea, Kiev`s security chief says.

Andriy Parubiy said they wanted to move them "quickly and efficiently" to mainland Ukraine, reports BBC.

Earlier, pro-Russian forces seized two naval bases - including Ukraine navy`s HQ - in Crimea. Kiev says its navy chief has been detained.

It comes a day after Crimean leaders signed a treaty with Moscow absorbing the peninsula into Russia.

A referendum in Crimea on Sunday, approving its split from Ukraine, came nearly a month after Kiev`s pro-Russian President Viktor Yanukovych was replaced by Western-leaning interim authorities.

In modern times, Moscow has staged three major invasions: Hungary in November 1956 and Czechoslovakia in August 1968, when the Communist governments there began showing dangerously Western tendencies; and Afghanistan in December 1979, when the pro-Communist regime was on the point of collapse.

These were huge and brutal operations, involving large numbers of tanks, and sometimes great bloodshed.

The takeover of Crimea has been completely different. This was an infiltration, not an invasion. And unlike in Hungary, Czechoslovakia and Afghanistan it was welcomed by a large proportion of the local population.

Nato Secretary General Anders Fogh Rasmussen has called the crisis in Crimea "the gravest threat to European security and stability since the end of the Cold War".

There were charged exchanges in a session of the UN Security Council, during which US envoy Samantha Power said her Russian counterpart Vitaly Churkin "showed more imagination than Tolstoy or Chekhov".

"Russia it seems has re-written its borders but it cannot rewrite the facts," said Ms Power, who was then accused by Mr Churkin of dropping "to the level of the tabloid press".

BDST:  1010 HRS, MAR 20, 2014