“It’s April 2022 but it seems like April 1937 when the whole world heard about one of your cities, Guernica,” he told lawmakers, referencing the carpet-bombing of the town by aircraft from Hitler’s “Condor Legion” during Spain’s 1936-1939 civil war in support of Francisco Franco’s nationalist forces.

Hundreds of people were killed, many of whom were at a weekly market in the town centre, in an atrocity that shocked the world and was immortalised in Picasso’s haunting anti-war painting.

Historians give an estimated death toll of between 150 and 300 people, while the Basque authorities give a much higher figure of 1,654.

Zelensky’s 10-minute videolink speech came after he addressed the UN Security Council for the first time, demanding it expel Russia over its brutal invasion and that Moscow be held accountable for its atrocities against civilians.

“We never thought that we would once again see shocking images of bombings and massacres of innocent people on European soil,” Spanish Prime Minister Pedro Sánchez said in brief remarks after Zelensky’s speech.

The Ukrainian leader’s latest addresses followed a wave of global outrage over the harrowing discoveries of civilian victims in Bucha and other towns near Kyiv after Russian troops pulled back.

So far, Ukrainian officials say over 400 civilian bodies have been recovered from the wider Kyiv region, many of which were buried in mass graves.

The Kremlin has denied any civilian killings and claimed that the images are fakes produced by Ukraine forces, or that the deaths occurred after Russian soldiers pulled out of the areas.

Europe’s worst conflict in decades has killed as many as 20,000 people, according to Ukrainian estimates.

Nearly 4.25 million Ukrainians have fled the country during Russia’s invasion, while a further 7.1 million are thought be internally displaced within Ukraine, the UN said Tuesday.