Andy Burnham has accused the Kremlin of “outrageous threats” against the UK as Russia warned of an escalation in tensions after the UK’s decision to present Ukraine with newly declassified blueprints to allow Kyiv to improve its production of long-range missiles.

Speaking in Kyiv, Burnham compared Ukraine’s struggle to Britain’s fight against Nazi Germany. “My nation kept the flame of European freedom alive in the 20th century, you hold that flame in the 21st,” Burnham said in a speech in front of St Sophia cathedral to mark the 35th anniversary of Ukraine’s independence.

“Despite Russia’s outrageous threats to my country, we will continue our support for Ukraine.”

In his first trip abroad as the prime minister, Burnham will give Ukraine previously classified information on the British manufactured components for long-range cruise missiles. The prime minister is also set to ink a new deal to share Ukrainian battlefield data with the UK’s Ministry of Defence and some private companies to train AI models.

Vladimir Putin’s spokesperson Dmitry Peskov said the exchange would add “fuel to the fire” and scupper any moves towards a peace deal.

Burnham hit back in an interview shortly after his speech. He said: “Who started the fire? That’s the question, isn’t it?”

During a conference call while in Kyiv with 34 leaders in the coalition of the willing, countries that have promised to help keep Ukraine secure in the event of a truce with Russia, Burnham also urged other nations to help Kyiv secure more US-made Patriot missiles.

He said the coalition was “doing everything we can all do and working with our allies outside of this coalition to dig into our own stocks and help others dig into their stocks”.

Moscow said it would identify and destroy the locations of missile production sites. “Britain is involved in this war on the side of the Kyiv regime,” Peskov told reporters. “Britain methodically and regularly adds fuel ‌to the fire, and methodically and regularly hatches schemes to prevent even the slightest progress in the peaceful settlement process.”

Kyiv was braced for another wave of Russian missile attacks as it marked Independence Day on Monday, attended by other European leaders alongside Burnham.

The prime minister’s decision to declassify the information about the UK-made components of the Storm Shadow/Scalp missiles will enable Ukraine to eventually build its own version, though this may take years.

In his speech, Burnham said Ukraine had “endured 12 years of naked aggression, the occupation of Crimea, and now four and a half years of Russia’s full-scale invasion, all aimed at crushing the independence that we are here to celebrate.”

He said: “Russia’s actions have not changed the path this nation is on. It’s confirmed it. You have stood tall and defiant in the face of everything Russia has thrown at you. And you have taken your place as a proud, sovereign European nation, a vibrant democracy with a bright future ahead.”

He said Europe owed a debt of gratitude to Ukraine for its fight. “I want to tell you something you probably don’t hear enough: thank you. Thank you all. Thank you. Thank you for the incredible stand you have taken because we are all stronger for it.”

The prime minister visited Ukrainian soldiers while in Kyiv, including joining them in playing a Smiths song on the electric guitar.

Speaking to reporters afterwards, he denied he was deliberately ramping up the rhetoric and said the decision to provide the new blueprints was a continuation of the longstanding UK policy to back Ukraine.

Asked by ITV News if he was “poking the Russian bear,” Burnham said: “Obviously with a change of prime minister people think there has been a change in policy. Well I’m here to say there isn’t. I’m going to do what our predecessors have done.

“If we don’t take a firm stand, who would be next? It’s right to do this. It’s in Britain’s interest to stand firm.”

Kyiv has said Russia is amassing more ballistic missiles and considering whether to mobilise an extra 300,000 soldiers. The missiles have been used to bomb Ukrainian infrastructure and warehouses, and to attack the capital, causing increased civilian casualties. There is a shortage of US-made Patriot interceptors, the only weapon that can effectively counter them.

Burnham swerved putting pressure directly on countries including Spain and Greece to hand over their own stockpiles of the weapons. He said the UK did not “have those systems to be able to hand over but we will certainly use whatever influence we have got. Obviously there are other threats that people are facing. It’s a complicated world right now.”

The UK has also announced it will help France set up assembly lines in Ukraine for long-range missiles, which the French president, Emmanuel Macron, promised last month. It has also previously announced that it will allow Ukraine to launch attacks with British-made drones, prompting warnings from Moscow that the UK will pay a “high price”.

Russia has withdrawn its ambassador to the UK, with no replacement in sight. The long-serving ambassador, Andrey Kelin, left last month after seven years in post, according to the Russian embassy in London. A spokesperson said that relations had “deteriorated to an unprecedentedly low level entirely on London’s initiative”. A UK government spokesperson said the UK’s ambassador would continue in post in Moscow.

Details of the Independence Day commemorations have not been made public amid fears of a Russian attack.

Macron and the German chancellor, Friedrich Merz, will attend the coalition of the willing meeting by video link. Burnham travelled to Kyiv with the president of the European Council, António Costa, and the prime minister of Luxembourg, Luc Frieden.

Volodymyr Zelenskyy is facing his biggest internal challenge after his former defence minister Mykhailo Fedorov called for the country to hold elections for the first time since the war began. The Ukrainian president has said any poll risks splitting the country and would be “a tsunami for the state”.