President Vladimir Putin has approved a draft treaty to make Crimea part of Russia, the Kremlin has said.
Putin signed an order"to approve the draft treaty between the Russian Federation and the Republic of Crimea on adopting the Republic of Crimea into the Russian Federation".
The order was part of a series of steps to bring Crimea into Russia after voters there approved the move in a weekend referendum that Ukraine and the West have called denounced by Ukraine and the West as "illegal".
An unusually frank Nato Secretary General issued an unequivocal warning on the course of events should Russia attack Latvia or Estonia.
The West responds with sanctions and closer political ties with Ukraine as Russia's President seals the annexing of Crimea to much fanfare.
Supporters of the controversial fracking industry believe shale gas could be America's most potent weapon in the stand-off with Russia.