MOSCOW : Ukraine on Thursday launched its largest drone attack on Moscow in years, sparking fires in and around the capital and forcing evacuations at the country's largest airport, officials said.

Unverified videos on social media purported to show large columns of black smoke over the city's skyline, while another showed drones buzzing overhead.

The large-scale attack came hours before Russian President Vladimir Putin was set to meet Southeast Asian leaders at a summit in the central city of Kazan, about 700 kilometres (435 miles) east of the capital.

Kyiv has stepped up its drone strikes on Russia in recent months, hitting oil refineries that fund Moscow's war chest, as diplomatic talks on ending the more than four-year conflict remain stalled.

"Air defence forces are continuing to repel a large-scale attack. Several drones managed to reach the MNPZ (Moscow Oil Refinery)," Moscow Mayor Sergei Sobyanin wrote on Telegram, with authorities closing traffic on streets near the refinery.

He did not specify damage to the facility, but several Russian media outlets reported that it was on fire.

Russia's busiest airport -- Moscow's Sheremetyevo -- announced it had evacuated passengers to "safe locations" during the barrage and was restricting flights.

Another drone crashed into an apartment building in the Moscow region district of Zhukovsky, while drone debris sparked a fire at a shopping centre near the capital's suburbs, Moscow region governor Andrey Vorobyov said.

Russian air defences shot down 180 drones on approach to Moscow, Sobyanin said, while the Russian defence ministry reported it had intercepted more than 500 Ukrainian drones overnight.

The attack was the largest on Moscow in at least two years, Russia's state TASS news agency reported.

Since the war began in 2022, Russia has pummelled Ukraine with near-daily aerial barrages of drones and missiles.

- Putin in Kazan -

The attack came just hours before Putin was set to host Southeast Asian leaders at a summit of the Association of Southeast Asian Nations (ASEAN) in the central city of Kazan.

Thailand, Vietnam, Cambodia, Laos, Malaysia and Singapore sent their prime ministers, while the Philippines sent President Ferdinand Marcos.

Putin has long sought to project stability in Russia, despite the economic and social effects of his four-year offensive on Ukraine.

Russia's economy -- on a war footing throughout the conflict -- is struggling with high inflation, a labour shortage and high borrowing costs.

The advance of forces on the Ukrainian battlefield has slowed this year, while Kyiv has multiplied attacks on Russian soil.

At a summit of the G7 in France earlier this week, US President Donald Trump said Moscow should "make a deal" to end the Ukraine war.

Putin has repeatedly refused offers for face-to-face talks with Ukrainian President Volodymyr Zelensky, saying that Moscow intends to capture Ukraine's eastern Donbas region by force.

Russia's 2022 offensive on Ukraine has become Europe's deadliest conflict since World War II, with hundreds of thousands killed and large parts of eastern and southern Ukraine ravaged by fighting.