Britain has warned Vladimir Putin not to use a deadly terror attack in Moscow as an “excuse” to intensify its war on Ukraine.

The Russian president used a speech on Saturday to accuse Kyiv of trying to help four alleged gunmen escape after they opened fire on unsuspecting victims in a concert hall, killing at least 130 people.

Islamic State claimed responsibility for the attack shortly afterwards as Ukraine denied any involvement. That assessment was backed up by the United States, who warned several weeks ago of an imminent terror attack in Moscow. 

IS released a selfie on Saturday of the men it said were involved along with details of how they planned and executed the ambush at Crocus City Hall.

However, in a five-minute video announcing the arrest of the perpetrators, Putin said: “They tried to hide and moved towards Ukraine, where, previously, a window had been prepared for them to cross the border.”

He also called the attackers “Nazis”, the Kremlin’s commonly used code word for Ukrainians.

A senior Whitehall security source told the Telegraph: “Putin’s desperation to put all of this on Ukraine is unsurprising, as he tries to further dupe the Russian people whilst pretending that there is no dissent within Russia.

“He must not use this confected connection as any sort of excuse for intensifying his illegal war in Ukraine.”

Alicia Kearns, the Conservative chairman of the Commons Foreign Affairs Committee, said: “Russian media channels are already circulating deep fake videos of Ukrainian officials in an attempt to blame Ukraine and provide Putin some defence for the war crimes he’s committing in Ukraine or worse, pretext for further atrocities.

“There is no indication of any link to Ukraine, nor any credible reason to suggest their involvement.”

Donald Tusk, the Polish prime minister, echoed that sentiment, saying he hoped “this terrible tragedy will not become a pretext for anyone to escalate violence and aggression”. 

Ukraine’s foreign ministry said they feared the accusations had the aim of “whipping up anti-Ukrainian hysteria in Russian society, creating conditions for strengthening the mobilisation of Russian citizens to participate in criminal aggression against [the] state”. 

US officials have privately voiced concern about unsubstantiated claims of Ukrainian involvement, suggesting that blaming Kyiv for the attack could be a way for Moscow to justify a further escalation or encourage more Russian recruits to the front line.

Washington DC’s public statements have so far gone no further than expressing condolences and strong condemnation of the attack.

But US officials were quick to confirm IS’ claim of responsibility for the massacre, perhaps to serve as an early counter against Russian claims of Kyiv’s involvement.

US intelligence gathered earlier in March found that Islamic State-Khorasan, known as IS-K, the branch of the group based in Afghanistan, had been planning an attack on Moscow, according to officials.