The Guardian view on Russian troops at Ukraine’s border: Putin’s plan B | Editorial

The military build-up on Ukraine's eastern border signals a change in strategy from Moscow

Provocation or preparation? And for what? The exact intentions informing the large-scale deployment of Russian forces close to Ukraine's eastern border remain opaque. But it seems increasingly clear that the tensions stoked by Vladimir Putin in the spring - when a prior military build-up took place - were the initial phase of a new approach rather than a one-off performative episode. After five years of frozen conflict, a worrying thaw appears to be taking place.

In April, having marched tens of thousands of troops to the Ukrainian border, Mr Putin announced a partial pull-back, to the relief of Kyiv and the west. It has since emerged that the retreat was merely superficial; troops stayed in the region and many of the tanks, ballistic missiles and assorted artillery remain in place. This hardware is now supplemented by an estimated 100,000 troops to the north, south and east of the Donbass region of Ukraine, controlled by pro-Russian separatists since 2014. Nato's secretary general, Jens Stoltenberg, warned Moscow this week against further provocation or aggressive actions" against an EU neighbour and ally. The US secretary of state, Antony Blinken, has said that any such aggression would be a serious mistake". But Tuesday's decision by the German energy regulator to temporarily suspend certification of the controversial Nord Stream 2 gas pipeline adds another unpredictable dimension to an unstable situation. The pipeline, which will allow Russia to bypass Ukraine when transporting energy to Germany, is seen by Kyiv as a threat to both its finances and security.