John Kerry: Russian action a 'brazen act of aggression'

Ukraine has ordered a full military mobilisation in response to Russia's build-up of its forces in Crimea.

In Crimea, Ukrainian soldiers faced off with Russian soldiers surrounding their bases while the Russian army is said to be digging trenches on the border with mainland Ukraine.

In an interview with ABC US Secretary of State John Kerry said Russian troops moving into the Ukrainian region of Crimea was "a brazen act of aggression".