Russia reacted with fury on Wednesday to Germany's decision to approve the delivery of Leopard 2 tanks to Ukraine, saying Berlin was abandoning its "historical responsibility to Russia" arising from Nazi crimes in World War Two.
Foreign Ministry spokeswoman Maria Zakharova said in a Telegram post that the move was confirmation of Germany's involvement in "a war planned in advance" against Russia.
The Russian embassy in Berlin said the decision - which paves the way for other NATO members also to send German-made tanks - would escalate the 11-month conflict in Ukraine, which Moscow casts increasingly as a perilous face-off between Russia and the US-led alliance.
"This extremely dangerous decision takes the conflict to a new level of confrontation," Ambassador Sergei Nechayev said. He added it would cause "irreparable damage to the already deplorable state of Russian-German relations".
There was no immediate reaction from President Vladimir Putin, who shortly after the announcement took part in a long televised meeting with students but referred only briefly to the "complicated" security situation facing Russia.
Kyiv and its Western allies say Russia's invasion of Ukraine, launched on Feb 24 last year, amounts to an unprovoked war of aggression aimed at seizing territory. Moscow says the West is using Ukraine to weaken Russia's own security.
Germany's decision on tanks followed weeks of agonising by the government of Chancellor Olaf Scholz, prompted by concerns about escalating the war and provoking Russia.
More than 80 years after their country invaded Soviet Russia and Ukraine in World War Two, some Germans recoil at the idea of sending tanks into a new conflagration there, out of a sense of historic guilt that the Russian embassy statement directly tapped into.
"Berlin's choice means the final refusal of the Federal Republic of Germany to recognise its historical responsibility to our people for the terrible, timeless crimes of Nazism during the Great Patriotic War, and the consigning to oblivion of the difficult path of post-war reconciliation between Russians and Germans," Nechayev said.
"With the approval of the leadership of Germany, battle tanks with German crosses will again be sent to the 'eastern front', which will inevitably lead to the deaths of not only Russian soldiers, but also the civilian population."
Kyiv has for months asked for Western tanks that it says it desperately needs to give its forces the firepower and mobility to break through Russian defensive lines and recapture occupied territory in the east and south.
Russia has repeatedly said foreign tanks will "burn" in Ukraine. It says they will only extend the war and prolong Ukrainian suffering, and that the West is "deluded" to think otherwise.