All of Moscow's airports were shut for hours, leading to hundreds of flight delays.

Ukraine on Thursday launched its largest drone attack on Moscow in years, sparking fires in and around the capital, hitting a major oil refinery and forcing evacuations at the country’s largest airport, officials said.

At least 17 people were wounded in the strikes, which also set a shopping centre and apartment building ablaze, according to authorities.

AFP reporters saw large columns of black smoke spreading over the capital’s southern skyline in dramatic scenes, while drops of rain mixed with soot fell from the sky.

The attack came as Russian President Vladimir Putin hosted Southeast Asian leaders at a summit in the central city of Kazan, about 700 kilometres (435 miles) east of Moscow.