UK condemns Russia’s destabilising nuclear rhetoric and RS-28 Sarmat missile signalling: UK Statement to the OSCE

Since the start of its illegal war of aggression against Ukraine, Russia has repeatedly employed irresponsible nuclear rhetoric and coercive signalling. On 12 May, Russia further underscored this trajectory by announcing the test launch of the RS-28 Sarmat intercontinental ballistic missile, a weapon which President Putin claims exceeds existing systems in range, payload, and ability to evade missile defences, and is due to enter service before the end of 2026.

The Sarmat test followed a series of other escalatory signals. Last week ahead of the Victory Day events, several participating states highlighted Russia's explicit threats of a large-scale strike on Kyiv. This accompanies a pattern of irresponsible nuclear rhetoric, including threats in March 2026 of a "symmetrical response" to completely unfounded allegations of nuclear transfers by the United Kingdom and France.

Such behaviour is fundamentally incompatible with Russia's OSCE commitments. The Helsinki Final Act commits participating States to refrain from the threat or use of force against the territorial integrity or political independence of any state. Nuclear coercion aimed at states supporting lawful self-defence violates this principle. The use of nuclear rhetoric intended to deter lawful assistance and fracture allied unity does not meet that standard.

The consequences are clear. As trust erodes, the risk of miscalculation increases; any reduced transparency over doctrine and force posture severely narrows the margin for error. When a participating State retreats from these frameworks while simultaneously intensifying nuclear signalling, the security environment deteriorates for all.

We will not be deterred from supporting Ukraine's right to self-defence. We call on all participating States to recognise Russia's irresponsible nuclear signalling for what it is: a deliberate effort to raise the perceived cost of collective resolve. European security depends on rejecting that strategy.