Any report about Ukraine these torrid days needs to come with a political health warning, even if that report originates from what might be called "our own" side. This includes the latest revelation from Nato about Russian troop deployments on the borders of eastern Ukraine.

Over the past six months, but especially since the collapse of Viktor Yanukovych's government in February and his circuitous flight from Kiev, there has been as much of a propaganda war as – potentially – a real war between Russia and the west. Two distinct, and for the most part mutually exclusive, versions of the truth have been put about, and have found receptive audiences on either side.

Russia saw Yanukovych's departure as the result of an illegal coup, orchestrated by dangerous rightwing nationalist elements. It discerned intervention by western, particularly US interests, in the formation of the interim government, and believed that these outside parties were driving events, the underlying purpose being to claim Ukraine for the west and do Russia down.

Western politicians and most of the media have taken a totally different view. Yanukovych was removed as the result of a genuine popular revolution. Russia annexed Crimea out of pique at what had happened, and in pursuit of Vladimir Putin's longstanding ambition to resurrect something like the Soviet Union. Next up would be eastern Ukraine, with its largely Russian-speaking and eastern-orientated population, and then – Moldova, perhaps even the Baltic states and Poland.

The latest Nato report has to be seen against this background. Its images purport to show Russian troops and hardware massing on the borders of eastern Ukraine. But there is one detail worth noting. Nato gives a date range for these pictures which makes them, essentially, historical. It is not at all clear that this situation pertains today.

Several more points could be made. The first is that several journalists have recently traversed the length of the eastern sector of the Russian-Ukrainian border, on the Russian side, and found nothing that would not correspond to the previously conducted exercises being wound down. They reported that the atmosphere seemed to be relatively relaxed; not the level of alert that might be expected of an army about to be aggressively deployed.

The second is that the US secretary of state, John Kerry, stated after his talks with Russia's foreign minister, Sergei Lavrov, that Russia had withdrawn a battalion from the area near the border with Ukraine. In other words, the trend was for de-escalation – to use western diplomats' term of the moment – rather than the opposite.

None of this, of course, means that Russia could not, or perhaps would not, move into eastern Ukraine if serious disorder broke out there and urgent calls came from Russian "compatriots" for help. And it is not beyond the bounds of possibility that such calls might be deliberately manufactured by Moscow. There is also such a thing as contingency planning.

But also to be borne in mind are the interests of the two sides. Moscow is unlikely to boast of any scaling back of its military presence near eastern Ukraine, lest it appear either to be bowing to western pressure or to be leaving those same east Ukrainian "compatriots" in the lurch. Domestically, it needs to keep up an appearance of readiness.

Something similar applies to the west and especially to Nato. The western alliance needs to project an impression of strength, both to maintain its own credibility (having failed to prevent Russia's annexation of Crimea) and to convince the Baltics and others who feel vulnerable that they are protected. To project strength, Nato requires a convincing enemy. A retreating Russia does not do the job.