Moscow has been forced to close all of its airports after the Russian capital was targeted by a swarm of Ukrainian drones just days before Friday’s high-profile Victory Day parade. It follows a warning by Volodymyr Zelenskyy that Russia may not be able to protect foreign officials attending the event, which this year marks the 80th anniversary of the defeat of Nazi Germany.

“Our position is very simple for all countries travelling to Russia on 9 May: we cannot be held responsible for what happens on the territory of the Russian Federation,” the Ukrainian president said over the weekend. “They are responsible for your safety. We will not provide any guarantees, because we do not know what Russia might do on those dates.”

Moscow's mayor, Sergei Sobyanin, said at least 19 Ukrainian drones had been intercepted "from different directions”, adding that debris had landed on one of Moscow's key highways.

Other Russian cities including Penza and Voronezh also reported drone activity.

Victory Day is already one of the most important in the Russian calendar.

The Soviet Union lost 27 million people in World War Two as it helped Western allies to encircle Hitler’s forces, pushing them back to to Berlin, where the red Soviet Victory Banner was raised over the Reichstag in 1945.

Because of this year’s special anniversary, Vladimir Putin is especially keen, experts say, to pull out all the stops.

Parade rehearsals have already shown that, unlike in recent years, Red Square will once again rumble with the sound of modern Russian main battle tanks and the goose-steps of front-line troops.

But the biggest difference will be “on the podium”, where Putun will be keen to show the West he is not isolated.

Unlike recent years, when the Kremlin was largely limited to friendly neighbours such as Belarus, this year’s parade is expected to feature leaders from the Brics bloc – countries aligned with Putin’s ambition to challenge the Western-led global order.

Top of the list is China’s Xi Jinping, who is due to arrive in Moscow on Wednesday for a three-day state visit. The Kremlin said he and Putin will discuss “comprehensive partnership and strategic interaction” and are expected to sign several documents.

Brazil’s President Luiz Inacio Lula da Silva, Vietnam’s President To Lament and Slovakian Prime Minister Robert Fico will also attend, joined by Belarus’ President Aleksandr Lukashenko.

Prime Minister Robert Fico criticised Zelenskyy’s warning.

"I reject such threats for security reasons," he said.

"I fully respect that the safety of participants is an internal matter of the Russian Federation. But if Mr Zelenskyy believes that his statements will force foreign delegations not to come, then he is deeply mistaken."

Some have already dropped out, however.

India’s Narendra Modi cancelled due to tensions with Pakistan, and Serbia’s President Aleksandar Vučić withdrew after falling ill during a visit to the US.

Putin has called for a ceasefire from 8–10 May – something Ukraine has declined to commit to. Kyiv has called for a longer truce.

Ukraine's objective may be to embarrass Russia, not inflict mass casualties, said Prof Mark Galeotti of the Royal United Services Institute.

“Russia is under no illusion that Ukraine can now strike as far as – indeed beyond – Moscow,” he said. “It’s been forced to build up its air defences, boost electronic warfare, and move into a general state of high alert.”

“But it’s monstrously unlikely that Zelensky will strike during the parade itself while foreign dignitaries are there. That would cross a diplomatic red line. Even states opposed to Russia don’t want that.”

Instead, Galeotti said, Ukraine is seizing an opportunity to expose Russia’s vulnerability. “Closing airports before foreign guests arrive, forcing them to land at regional airfields and be driven in – it all sends a clear message that this war is not going how Putin hoped.”

He added: “We should expect more Ukrainian attacks before and immediately after the celebrations – attempts to embarrass Putin and show that whatever he does, he simply cannot protect Moscow.”