Moscow and Kyiv traded a barrage of drone attacks ahead of the parade -- which has become a key event during Vladimir Putin's 25 years in power -- as US talks pushing for an end to the conflict appeared stalled.

US Vice President JD Vance called Wednesday on the two sides to enter direct talks. "We think it's probably impossible for us to mediate this entirely without at least some direct negotiation between the two," he said.

Moscow will hold the Victory Day event on Red Square to mark 80 years of the defeat of Nazi Germany, an anniversary that comes more than three years into its Ukraine offensive.

Ukrainian President Volodymyr Zelensky said a Russian attack had killed a mother and her son in Kyiv on Wednesday.

Russia fired 187 drones and five ballistic missiles at Ukraine between late Tuesday and Wednesday afternoon, said Kyiv's air force.

Russia said Ukraine had launched a barrage of drones at Moscow and other cities in western Russia, forcing airports to halt traffic with 60,000 people seeing their flights disrupted.

- 'All necessary measures' -

The attacks come with foreign leaders such as China's Xi Jinping due to arrive in the Russian capital for the WWII celebrations.

"Our military and special services are taking all necessary measures to ensure that the celebration of the great victory takes place in a calm, stable and peaceful atmosphere," said Kremlin spokesman Dmitry Peskov.

He added that the authorities were jamming the internet because of a threat from Kyiv, which has hit Russian cities with drones throughout Moscow's offensive.

The Kremlin's forces occupy a fifth of Ukraine and this spring hit the country with a string of deadly attacks on civilian areas.

"We need to take into account that dangerous neighbourhood that we have," Peskov said, referring to Ukraine.

"As long as guests are here, until May 10, we need to be ready for restrictions," he added, calling on Muscovites to be understanding.

- 'Nothing scares us' -

Russians from outside Moscow visiting the heavily policed capital for the parade appeared unfazed.

"We are from Rostov-on-Don. Nothing scares us," said 22-year-old student Valeria Pavlova. The southern city serves as a command and logistics hub for the Ukraine offensive and has regularly been targeted.

"It's much calmer here," she added.

But scenes at airports in Moscow, Saint Petersburg and other cities were more chaotic.

Kyiv's drone attacks disrupted some 350 flights Tuesday and Wednesday, Russia's Association of Tour Operators said. Social media videos showed people sleeping on the floor and airports with rows of over a dozen planes queueing on the tarmac.

Ukraine's airspace has been forced to close since Russia launched its offensive in February 2022.

Putin has ordered a three-day ceasefire in Ukraine starting at midnight Wednesday, which Ukraine has dismissed as a "game" designed to protect his parade rather than a genuine peace measure.

Kyiv has instead called for an unconditional 30-day ceasefire, something Putin previously rejected.

French President Emmanuel Macron said Wednesday that Russia would "undoubtedly" not respect its own order to halt fighting and questioned if the Russian leader was "serious" about a durable peace.

- Foreign leaders -

Hours before Putin's order was set to come into effect, Moscow unleashed a barrage of drone attacks across Ukraine and Zelensky called for more pressure on Russia to end its offensive.

The Kremlin said Putin's order remained in force but that Russia would retaliate to any attacks.

Russia's army, meanwhile, claimed the capture of a small village in the eastern Donetsk region of Ukraine.

Putin, who has been largely isolated by the West since launching his offensive, is due to meet visiting leaders throughout Wednesday.

He was due to sign a strategic partnership treaty with Venezuela's Nicolas Maduro -- Russia's longtime partner -- and hold talks with the leaders of Cuba, Mongolia and the Republic of the Congo on Wednesday.

Serbian President Aleksandar Vucic and Slovakia's Prime Minister Robert Fico are also among the 29 foreign leaders set to attend. Fico, the only EU leader visiting, has defied Brussels by travelling to Moscow for the parade.

And Chinese troops are among some of the foreign soldiers set to march during the May 9 parade, despite a warning from Kyiv not to do so.