Russia's ambassador to the Organization for Security and Co-operation in Europe was told 'it will not work' in Vienna on Thursday, as the UK issued a blunt four-word warning in response to Russia's latest 'sleep well' threat over the Ukraine conflict. British envoy Neil Holland used the OSCE meeting to insist the UK 'will not be deterred' from supporting Ukraine, directly answering recent Kremlin rhetoric aimed at countries arming Kyiv.
The news came after senior Russian official Dmitry Medvedev, a former president and now deputy chairman of Russia's Security Council, told Western leaders that European facilities producing drones and other equipment for Ukraine were 'potential targets' for Russian forces. Medvedev, who has become one of Moscow's most aggressive public voices since the full-scale invasion began in 2022, ended his warning with a pointed sign-off to European governments: 'Sleep well, European partners!'
Russia-Ukraine Conflict Centre Stage At OSCE
Russia has repeatedly accused the West of escalating the Russia-Ukraine conflict by supplying weapons, ammunition and training to Kyiv. Western governments, including the UK, frame their role very differently, arguing that Ukraine is exercising its right to self-defence against what they call an illegal and unprovoked invasion.
In his statement to the OSCE, Holland said Russia's latest language at the Vienna gathering reflected 'a familiar attempt to intimidate and deter those who support Ukraine's right to defend itself.' He criticised what he described as Russia's 'disregard for agreed rules,' accusing Moscow of trying to recast its own offensive war as a defensive response to NATO and EU policies.
'The Russian state characterises international support for Ukraine's defence against its deadly attacks as an escalation of the conflict,' Holland said, according to remarks reported by the Express. 'A claim that is unfounded and aimed at deflecting from its own actions.'
His four-word retort — 'It will not work' — was aimed squarely at Medvedev's earlier suggestion that European arms and drone production lines could be hit. Coming in the formal, often restrained setting of the OSCE, it amounted to an unusually terse and personal pushback.
UK's Message To Moscow: Ukraine Support 'Will Not Be Deterred'
Holland went on to underline that the UK sees its Ukraine policy as both legal and necessary. 'Our support for Ukraine, and readiness to defend ourselves, is lawful and necessary in response to Russia's continued aggression,' he told fellow delegates.
He then delivered the UK's clearest line of the day: 'The UK will not be deterred. The UK will continue to provide the military assistance Ukraine needs, for as long as it needs it.'
Since Russia's full-scale invasion in 2022, Britain has been one of Kyiv's most active backers, supplying air defence systems, armoured vehicles and long-range missiles, as well as training Ukrainian troops on UK soil. London has regularly presented that support as a test of European security more broadly, arguing that allowing Russia to succeed would embolden further aggression.
I welcome today’s decisions to move forward with the €90 billion EU loan for Ukraine and adopt the 20th sanctions package on Russia.
— Helen McEntee TD (@HMcEntee) April 23, 2026
These decisions give Ukraine certainty over the financing it needs in the face of continuing Russian aggression and keeps the pressure on Russia to end its brutal war.
— Helen McEntee TD (@HMcEntee) April 23, 2026
We now need to move quickly to implement both. Ireland and the EU will continue to stand with Ukraine.
Holland said Russia's continuing missile and drone strikes on Ukrainian cities showed 'contempt for international law' and for civilian life. His language left little doubt that the UK sees Moscow's threats against defence manufacturers in Europe as part of the same pattern.
Russian officials, for their part, insist they are responding to what they see as a Western proxy war on their borders. They accuse NATO states of fuelling the Russia-Ukraine conflict and claim that new weapons deliveries cross supposed 'red lines.' Those assertions, repeated in Moscow's messaging at the OSCE, have not been backed by independent evidence, and Western governments have generally treated them as political positioning designed to unsettle public opinion.
Detained OSCE Staff Become Flashpoint In Russia-Ukraine Conflict
Holland also used the Vienna session to highlight a lesser-known but highly charged issue linked to the Russia-Ukraine conflict: the fate of three former members of the OSCE's Special Monitoring Mission in eastern Ukraine.
Dmytro Shabanov, Vadym Golda and Maxim Petrov have been held by Russia and its allies for four years, according to the UK. The Special Monitoring Mission was the OSCE's civilian field operation, once tasked with documenting ceasefire violations and conditions along the contact line before Russia launched its full-scale invasion.
Calling for their immediate and unconditional release, Holland said their continued imprisonment 'forms part of a broader pattern of obstructing independent observation, rejecting accountability, and weakening the institutions designed to reduce risk and build security.'
The British intervention again placed OSCE structures at the heart of the dispute. The organisation, which includes both Russia and Ukraine, was originally conceived as a forum to reduce tensions and prevent conflict in Europe. In practice, its meetings have become a running argument over the causes and conduct of the war.
Whether Moscow will treat the UK's four-word warning as bluster or as a line in the sand remains to be seen. What is clear from the Vienna exchanges is that Russia's threats and Britain's response are now part of a larger contest, not only on the battlefield but also over who gets to define the rules that still claim to govern European security.
