Russian President Vladimir Putin has shifted the Ukraine crisis into a new, more dangerous phase with a barrage of words and actions that suggest his ultimate aims go far deeper than extending Russian sway over two struggling separatist regions.

Putin signed friendship treaties on Monday night with the so-called Donetsk and Luhansk people's republics proclaimed by Russian-backed separatists in eastern Ukraine, a move denounced as illegal by the West and met with immediate sanctions, including on Russian banks and a major new gas pipeline.

But it was the extraordinary televised speech preceding the signing that offered deeper clues to Putin's thinking, with the Russian leader twisting centuries of history into an hourlong diatribe portraying Ukraine as an artificial nation with no tradition of statehood.